ASE A5 BRAKES

Question 0

Technician A says that, if a brake line gets damaged, you can repair it with a hose and protected hose-type clamps.
Technician B says that some master cylinders are the quick take-up type. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 0

Technician B is correct. Brake lines should always be replaced with specially-made brake lines. Bends and flares can be created by the installing technician using the proper tools. Regular steel tubing and rubber hosing will not withstand the pressures present in a brake system. Some master cylinders are quick take-up masters which pull the fluid back into the reservoir, thus retracting the caliper pistons.

The correct answer is B.

Question 1

Technician A says that some diesels use a hydraulic booster not a vacuum booster.
Technician B says a hydraulic booster gets its power from the power steering pump. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 1

Both technicians are correct. Since diesel engines generate so little vacuum, most use a hydraulic booster system instead of a vacuum booster system; thus, Technician A is correct. Technician B is also correct because hydraulic brake boosters receive their hydraulic pressure from the power steering pump.

The correct answer is C, both technicians are right.

Question 2

Technician A says that you must lube the anchor plate on a dual-servo design brake system when servicing.
Technician B says that, when servicing a dual-servo design brake system you should always replace the springs. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 2

Only a leading-trailing type design brake has an anchor plate so Technician A is incorrect. You can test the springs by dropping them on the floor and listening for a thud, if they make a spring like twang noise they need to be replaced. So technician B is wrong also.

The correct answer is D, neither technician is right.

Question 3

Technician A says that, when installing the brake shoes on a dual-servo design brake system, you must pay attention to where the primary shoe in installed as well as the secondary shoe.
Technician B says that the adjusting link must be tested and lubed. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 3

Both technicians are correct. If the primary and secondary brake shoes are installed in the incorrect locations, the brake system will not work properly. The adjusting link should be adjusted and lubed to ensure that it is properly adjusted so that the shoes apply properly and lubed so that it does not bind and fail.

The correct answer is C, both technicians are right.

Question 4

Technician A says that a leading-trailing brake design has a lot of adjustment links and pivot points.
Technician B says that a leading-trailing brake design has very few adjustment links and pivot points. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 4

Technician B is correct. The dual-servo design has more adjustment links and pivot points and is a more complicated design.

The correct answer is B.

Question 5

Technician A says that both brake designs use a pawl to adjust the brake automatic adjuster.
Technician B says that only the dual-servo design uses a star wheel or ratchet type adjuster. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 5

Technician A is correct. Both designs use star or ratchet type adjusters, so technician B is incorrect.

The correct answer is A.

Question 6

Technician A says that some brake shoes have one shoe longer than the other on the same wheel brake.
Technician B says that this is only true on riveted brake shoes. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 6

Technician A is correct. One shoe may be longer or shorter depending on whether it is the primary or secondary shoe; riveted or bonded makes no difference. So Technician B is incorrect.

The correct answer is A.

Question 7

Technician A says that, if you cannot get the brake drum off of the spindle, you may have to back off the adjuster wheel. Technician B says that, if you can’t get the brake drum off the spindle, you might have a ridge on the drum rim that must be removed by machining. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 7

Both technicians are correct. The lug nuts may also be rusted to the lug nut holes in the drum.

The correct answer is C, both technicians are right.

Question 8

Technician A says that on a dual-servo design brake system, the rearward facing or secondary shoe does most of the braking. Technician B says that on a leading-trailing brake design, the leading or forward facing shoe does most of the braking. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 8

Technician A is correct. In a leading-trailing brake design, both shoes work equally.

The correct answer is A.

Question 9

Technician A says that a typical brake drum backing plate has eight support pads.
Technician B says that the part of the brake shoe that the springs attach to is called the web. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 9

Technician B is correct. Most brake drum backing plates have six support pads, three per shoe. The part of the brake shoe that is perpendicular to the friction material which the springs attach to is called the web.

The correct answer is B.

Question 10

Technician A says that some manufacturers do not recommend honing the wheel cylinders, only replacement.
Technician B says that many vehicle manufacturers recommend that wheel cylinders not be honed because of the special surface finish inside the bore. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 10

Nether is correct. Although we mostly replace wheel cylinder these days due to the cheap cost of the part and the high cost of labor, wheel cylinders can be honed and rebuilt with no problem.

The correct answer is D, neither technician is right.

Question 11

Technician A says that you should lube the backing plate pads with synthetic brake grease, lithium brake grease or anti-seize compound before installing the brake shoes.
Technician B says that no grease of any kind should be installed within the brake drum area as it will get on the brake shoes and destroy the brakes. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 11

Technician A is correct. The backing plate pads, anchors, and adjusters must all be lubed during service. Care must be taken to not get any lube on the friction material of the brake shoes. Normally lithium grease is used.

The correct answer is A.

Question 12

Technician A says that gas fade is less likely with disc brakes than drum brakes.
Technician B says that disc brakes are more likely to experience water fade than drum brakes. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 12

Technician A is correct. Gas fade is much less likely with disc brakes. Technician B is incorrect because drum brakes are much more likely to experience water fade problems.

The correct answer is A.

Question 13

Technician A says that you must adjust the disc brakes every 6000 miles or use the manufacturer’s recommended intervals. Technician B says that drum brakes are mostly self adjusting on modern vehicles. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 13

Technician B is correct. Most rear drum brake systems are fully self-adjusting. Technician A is incorrect because, as the pads wear, the caliper and master cylinder automatically compensate for the pad wear.

The correct answer is B.

Question 14

Technician A says that brake noise, squeaking or squeals, are caused by high-frequency rattling or vibration of the brake pads. Technician B says that some disc brake pads have a metal wear indicator that will squeal when the pads are low. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 14

Both technicians are correct. The easiest way to ensure that new brake pads don’t squeal is to use pad adhesive, make sure a non-directional finish is put on the rotors when machined, and bevel the edges of the pads so they can’t catch in any leftover grooves in the rotors. Most newer brake pads have metal wear indicators that will squeal during normal driving when the pads reach a certain percentage of wear.

The correct answer is C, both technicians are right.

Question 15

Technician A says that some brake rotors are vented and some have holes drilled in the face for better cooling.
Technician B says that most vehicles today have machineable rotors. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 15

Technician A is correct. Cross drilling and venting help cool the rotors. Technician B is incorrect because the rotors on most of today’s smaller cars are smaller throwaway rotors that save weight, helping to increase gas mileage.

The correct answer is A.

Question 16

Technician A says that most small cars come with fixed calipers on the front brakes.
Technician B says that floating and sliding calipers are only used on high dollar exotic cars and are not very common on today’s vehicles. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 16

Both technicians are incorrect. Most cars today use floating or sliding calipers. Fixed calipers are best suited for heavy duty use because of the increased weight and size.

The correct answer is D, neither technician is right.

Question 17

Technician A says that tapered wear on a brake pad can be caused by caliper flex.
Technician B says that one pad worn out on one side of a floating caliper is because the caliper is frozen and needs to be replaced. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 17

Technician A is correct. Caliper flex is the unequal movement of the caliper during engagement, where one side moves more than the other. This creates tapered wear on the pads. Technician B is incorrect because when the pad on one side is being worn more than the other, the guide pins are frozen. This condition prevents the caliper from moving to engage the other pad properly.

The correct answer is A.

Question 18

Technician A says that the seal on a caliper piston is like a big “o” ring and can be easily replaced.
Technician B says that the seal on a caliper piston returns the piston back to it’s original position when the brake pedal is released. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 18

Both technicians are correct. The caliper piston seal resembles a square cut O-ring. This seal is easily replaced during caliper overhaul. Technician B is correct because the purpose of the caliper piston seal is to keep the brake fluid within the caliper bore, and it has some bearing on the retraction of the piston as it returns from its deflected position. Retraction of the piston is also caused by the release of fluid pressure and the spring on the piston in the master cylinder.

The correct answer is C, both technicians are right.

Question 19

Technician A says that some rear disc brakes have small brake shoes to use as the parking brake.
Technician B says that some rear disc brakes use a screw and lever system inside the caliper as rear parking brakes. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 19

Both technicians are correct. The pads on rear disc brakes don’t need to be as big as those on the front brakes since most braking power is applied by the front brakes. Screw and lever systems inside rear disc brake calipers are used to apply the parking brake. When servicing these calipers, the pistons must be screwed back into their bore, not compressed.

The correct answer is C, both technicians are right.

Question 20

Technician A says that the brake pad edge code letters of “FF” mean noise level rating.
Technician B says semi-metallic brake pads are made by a process called sintering. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 20

The brake pad letter codes are for the rating of the coefficient of friction, not noise. So technician A is incorrect. Technician B is correct.

The correct answer is B.

Question 21

Two technicians are discussing the reason that the brake fluid drops in a master cylinder.
Technician A says that it may be due to normal wear of the disc brake pads.
Technician B says low fluid level may be due to a leak in the hydraulic system. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 21

Both technicians are correct. Since disc brakes make up for pad wear by displacing more fluid in the caliper; low fluid level can be caused by pad wear. Low fluid level may also be caused by a leak in the hydraulic system. When the master cylinder fluid level is low, a full brake system inspection should be performed to determine the cause.

The correct answer is C, both technicians are right.

Question 22

Technician A says that as you go up in altitude, vacuum drops in pressure.
Technician B says that as you go up in altitude, atmospheric pressure drops. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 22

Technician B is correct. Vacuum is a lack of pressure. It can also be defined as a pressure below that of atmospheric pressure. Atmospheric pressure is measured as the weight of a column of air upon a measuring device. As altitude increases, the size of the column of air decreases; thus, atmospheric pressure decreases as altitude increases, making Technician B correct.

The correct answer is B.

Question 23

Technician A says that you need a power booster because disc brakes have no servo-action.
Technician B says that a brake booster uses pressure off of the intake manifold. Who is correct?

A. Technician A only

B. Technician B only

C. Both A and B

D. Neither A or B

Answer 23

Technician A is correct. The brake booster receives a vacuum signal from the intake manifold, not pressure; thus, Technician B is incorrect.

The correct answer is A.

Question 24

Technician A says that a brake booster works because it has vacuum on one side of a diaphragm and atmospheric pressure on the other. Technician B says that a diesel engine has too much vacuum and must have a vacuum reducer installed in the line to the booster. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 24

Technician A is correct. A vacuum-assist brake booster has a diaphragm in the center of the booster on one side on which is pushing atmospheric pressure on the diaphragm and on the other is vacuum pulling on the diaphragm. Technician B is incorrect because a diesel engine has little to no vacuum from the engine and must have an auxiliary vacuum pump to make a vacuum booster work. The correct answer is A.

Question 25

Technician A says that some vehicles use a dual vacuum booster mounted side by side to increase booster performance. Technician B says that the larger around the booster is, the more pressure is applies. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 25

Technician B is correct. The larger a booster diaphragm is, the more pressure it applies, so Technician B is correct. A dual booster is mounted one in front of the other, not side by side, so Technician A is incorrect. The correct answer is B.

Question 26

A brake pedal feels spongy when depressed. Technician A says that a defective vacuum booster could be the problem. Technician B says that a defective hydraulic brake booster could be the problem. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 26

Neither technician is correct. A spongy feeling brake pedal is caused by air in the system. Defective boosters would cause a heavier than normal feeling in the brake pedal. The correct answer is D, neither technician is right.

Question 27

Technician A says that to increase braking performance you can add DOT 5 brake fluid to any brake system. Technician B says DOT 3 brake fluid should only be used in DOT 3 systems. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 27

Technician B is correct. Very few brake systems are rated for the use of DOT 5 brake fluid. It should NEVER be used in systems not specifically made to handle it. DOT 4 fluid CAN be used in DOT 3 systems but not vice versa. The correct answer is B.

Question 28

Technician A says that DOT 5.1 brake fluid is a severe duty brake fluid and has a boiling point over 500 degrees. Technician B says DOT 5.1 can be mixed with DOT3 or DOT 4 systems but that you should check manufacturer's recommendations. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 28

Both technicians are correct. DOT 5.1 brake fluid is severe-duty rated for much higher operating temperatures than DOT 3 and 4. It can be used in systems designed for lower DOT ratings; however, manufacturer recommendations must be followed to avoid damage to the system. The correct answer is C, both technicians are right.

Question 29

Technician A says that you can use any double flare end line with ISO fittings with no problem as they are interchangeable. Technician B says that the brake line is double walled and has a corrosion coating. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 29

Technician B is correct. Technician A is incorrect because ISO and double flare are two completely different systems and may not be interchanged. Technician B is correct because metal/steel brake lines are double-walled and have a special corrosion-resistant coating. The correct answer is B.

Question 30

Technician A says that a pull to the right during braking could be caused by a defective metering valve. Technician B says that a pull to the right during braking could be caused by a defective proportioning valve. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 30

Technician B is correct. A metering valve splits the braking pressure between front and rear, so is very unlikely to be able to cause a pull during braking. Proportioning valves divide hydraulic pressure between sides, so they can cause brake pull. Thus, Technician B is correct. A hung caliper not fully applied could also cause a brake pull. The correct answer is B.

Question 31

Technician A says that some wheel speed sensors produce an analog signal. Technician B says that some wheel speed sensors produce a digital signal. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 31

Both technicians are correct. There are two types of wheel speed sensors, analog and digital. Which one a particular system/car uses is dependent upon the manufacturer. Thus, both technicians are correct. The correct answer is C, both technicians are right.

Question 32

Technician A says that maximum traction between a tire and the road occurs when the tire is rotating freely. Technician B says that a pulsating brake pedal during normal braking is something ABS systems do and is ok. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 32

Technician A is correct. When the tire is able to rotate freely, maximum traction occurs. Technician B is incorrect because the brake pedal in a car equipped with ABS should only pulsate under extreme braking conditions, not normal braking. The correct answer is A.

Question 33

Technician A says that ABS allow you to be able to stop without skidding even in snow and ice. Technician B says that steering is possible when the ABS is engaged during a stop. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 33

ABS does not work correctly on snow and ice. It is designed to allow the driver to retain steering control under extreme braking conditions by preventing wheel lockup. While it will help somewhat on snow and ice, use in these conditions will be erratic unless special tires or traction devices are used. Technician B is correct because ABS is designed to enhance steering control under extreme braking loads. The correct answer is B.

Question 34

ABS is being discussed. Technician A says that some ABS sensors are mounted in the rear-axle pinion gear area. Technician B says all ABS systems mount the wheel speed sensors at the wheels. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 34

Technician A is correct. Technician B says ALL, so he is incorrect because ABS sensors can be mounted in either location. The correct answer is A.

Question 35

Technician A says all ABS systems use four ABS sensors at each wheel. Technician B says there are one-channel, two-channel, three-channel and four-channel ABS systems. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 35

Technician B is correct. ABS systems have anywhere from one to four sensors per wheel, depending on the number of channels. The correct answer is B.

Question 36

Technician A says ABS sensor dash lights are red in color. Technician B says brake hydraulic sensors are amber in color. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 36

Neither technician is correct. Both have it backwards. Sensor warnings are red because they are more important. ABS indicator lights are amber in color. The correct answer is D, neither technician is right.

Question 37

Technician A says that some ABS systems are hooked up to traction control systems. Technician B says that ABS systems must have special scan tools to diagnosis them. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 37

Technician A is correct. Vehicles with OBDII systems use a single scan tool for diagnostics of all systems. The correct answer is A.

Question 38

Technician A says when inspecting an ABS sensor, you can use a scope to see the sensor output. Technician B says that the scope will show the tone ring teeth moving past the sensor. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 38

Both technicians are correct. The signal trace you see on the scope is the toning teeth moving past the sensor. The correct answer is C, both technician are right.

Question 39

Technician A says some ABS sensors must be adjusted with a steel feeler gauge. Technician B says that some sensors come with a built-in paper or plastic to set the depth of the sensor. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 39

Technician B is correct. ABS sensors are magnetic sensors; thus, a steel feeler gauge will stick to it and give an incorrect setting. The feeler gauge must be plastic or some nonferrous metal. The correct answer is B.

Question 40

Technician A says that a yaw sensor is used to determine a deviation in the driver's intended direction. Technician B says the steering wheel position sensor tells the computer when there is a deviation in the driver's intended direction. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 40

Both technicians are correct. The yaw sensor and steering wheel position sensor work in tandem. The correct answer is C, both technicians are right.

Question 41

Technician A says that some master cylinders are dual master cylinders and have two pistons side by side. Technician B says that some master cylinders are diagonal systems and split the front and rear brakes diagonally. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 41

Technician B is correct. Dual master cylinders have the two pistons lined up one in front of the other. Diagonal split systems pair opposite corners. The correct answer is B.

Question 42

Technician A says that, if the front brake reservoir chamber is over filled and the rear chamber is empty, it is called bypassing and the master cylinder should be replaced. Technician B says that, if you have a lower-than-normal brake pedal, you should adjust the rod length until there is no freeplay at the pedal. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 42

Technician A is correct. A master cylinder that is bypassing is leaking fluid past the internal seals. The brake pedal will also slowly sink to the floor when enough pressure to hold the pedal down is applied when the master is bypassing. A low brake pedal is most likely either a leak, insufficient friction material remaining on the pads or shoes, or an improperly adjusted rear brake set. The correct answer is A.

Question 43

Technician A says that, when installing a master cylinder, you only need to bolt it to the power booster and then add the brake fluid to avoid getting fluid on the vehicle's paint. Technician B says that, when installing a brake caliper, you should press the piston back in first to push fluid back into the master cylinder to insure no air gets into the system. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 43

Neither is correct. When installing a master cylinder, you should always bench bleed it first to remove all air prior to installation. Brake systems should never be back flushed by compressing the piston. Hold pressure on the piston and crack open the bleeder screw to compress the caliper piston. The correct answer is D, neither technician is right.

Question 44

Technician A says that, if the brake fluid is low, then the brakes could be worn down close to replacement and should be inspected. Technician B says that, if the brake fluid is low, there could be a leak in the hydraulic system. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 44

Both technicians are correct. Low fluid in the master cylinder reservoir can be a sign of worn friction material and/or leaks in the system. Both should be inspected thoroughly. The correct answer is C, both technicians are right.

Question 45

All of these are true about the metering valve except: A. It is used on vehicles with front disc and rear drum brakes. B. It is a height sensing device. C. It achieves even braking by allowing rear drum brakes to apply just before the front disc brakes. D. It is often part of the combination valve.

Answer 45

Answer A is wrong. This is an except question. It is used on most vehicles with front disc and rear drum brakes. Answer B is correct. A height sensing proportioning valve controls pressure to the rear brakes. It's used to prevent wheel lock up. Answer C is wrong. The metering valve gives the rear brakes a chance to over come the springs and engage with the front brakes. Answer D is wrong. This is an except question. It is often part of the combination valve.

Question 46

A vehicle's brake lights are completely inoperative. Technician A says the brake light switch may be stuck closed. Technician B says the circuit may have shorted and blown a fuse. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 46

Answer A is wrong. A closed brake switch would leave the brake lights on not off. Answer B is correct. If both brake lights are out, start troubleshooting with a quick check of the circuits fuse. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 47

A vehicle with vacuum assisted power brakes has a hard brake pedal and is difficult to stop. Technician A says the vehicle may have a frozen front brake caliper. Technician B says it may have a problem with the brake booster system. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 47

Answer A is wrong. If the vehicle has a frozen front caliper it will pull to the other side while braking. Answer B is correct. Pump the brake pedal numerous times to relieve the vacuum from the brake booster. After relieving the vacuum, start the engine, the pedal should move slightly toward the floor. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 48

Technician A says a micrometer is the preferred tool used to check a rotors lateral runout. Technician B says a dial indicator is the preferred tool used for measuring rotor thickness. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 48

Answer A is wrong. Neither Technician A or B is correct. Answer B is wrong. Neither Technician A or B is correct. Answer C is wrong. Neither Technician A or B is correct. Answer D is correct. A micrometer is used for measuring rotor thickness. A dial indicator is used to measure lateral runout.

Question 49

A technician is measuring the inside diameter of a brake drum with a brake drum micrometer. The technician should use which of the following measurements. A. The smallest measurement. B. A brake drum tool is not used. C. The average of all the measurements. D. The largest measurement.

Answer 49

Answer A is wrong. When measuring the inside of a brake drum the largest not the smallest measurement is used. Answer B is wrong. A brake drum inside micrometer is used to take this measurement. Answer C is wrong. It is not the average, it's the largest because the inside wears making the inside diameter larger. Answer D is correct. The largest measurement is used.

Question 50

A vehicle pulls to the left only when the brakes are applied. Technician A says this could be a restricted left front brake line. Technician B says this could be a frozen right front caliper. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 50

Answer A is wrong. A restricted LF brake line will cause the vehicle to pull to the right when braking. Answer B is correct. A frozen RF caliper will cause the vehicle to pull to the left when braking. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 51

A vehicle has a low brake pedal. Technician A says an improperly adjusted brake pedal could be the cause. Technician B says overheated brake fluid could cause this condition. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 51

Answer A is wrong. Both Technicians are correct. Answer B is wrong. Both Technicians are correct. Answer C is correct. An under adjusted brake pedal will cause a low brake pedal. Excessive heat damages brake fluid resulting in a spongy or low brake pedal. Answer D is wrong. Both Technicians are correct.

Question 52

A technician is lubricating rubber brake components while performing a brake job. Technician A says a high temperature silicon based lubricant would work. Technician B says a good petroleum based lubricant would work. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 52

Answer A is correct. Use high temperature silicon based lubricant that does not contain petroleum. Answer B is wrong. Petroleum based products can cause swelling resulting in brake unit failure. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 53

Technician A says that two different size tires on the rear of a vehicle will not hamper ABS operation. Technician B says some ABS systems use an accumulator that holds brake fluid under high pressure. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 53

Answer A is wrong. Different size tires will affect the signal from the speed sensors. Answer B is correct. Some ABS systems use an accumulator that holds brake fluid under high pressure. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 54

The rear wheels of a vehicle are locking up only when the brakes are applied. Which of these is most-likely the cause? A. The metering valve B. The pressure differential switch C. The proportioning valve D. The brake switch

Answer 54

Answer A is wrong. The metering valve delays front brake application. They provide for balanced braking. Answer B is wrong. The pressure differential switch warns the driver of a hydraulic leak. Answer C is correct. The proportioning valve prevents rear wheel lockup. Answer D is wrong. The brake switch is part of the brake light system.

Question 55

Technician A says to use the original brass washer when installing a new flexible brake hose. Technician B says to use a compression fitting to repair a small leak in a stainless steel brake line. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 55

Answer A is wrong. Always use the new washer when replacing a brake hose. Answer B is wrong. Never use a compression fitting on a brake line. Answer C is wrong. The correct answer is D. Answer D is correct. Neither technician is correct.

Question 56

A integral drum parking brake system is being discussed. Technician A says a binding cable will prevent parking brake application. Technician B says the brake strut is part of the parking brake system being discussed. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 56

Answer A is wrong. These are mechanically operated systems. A binding or misadjusted parking brake cable will affect parking brake performance. Answer B is wrong. The brake strut is part of the integral drum parking brake system. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 57

Two technicians are discussing brake backing plates. Technician A says if a ridge has formed on the pads where the shoes rest they may be filed to restore a smooth finish. Technician B says to apply bearing grease to reduce brake squeak. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 57

Answer A is correct. The ridge often formed by the movement of the brake shoe may be filed smooth. Answer B is wrong. It's important to use high temperature grease between the backing plate and the shoe. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 58

A vehicle has a low spongy pedal. Technician A says it could be loose wheel bearings. Technician B says that the low brake pedal is more likely caused by worn brake pads. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 58

Answer A is correct. Loose wheel bearings will result in a low spongy brake pedal do to excessive movement. Answer B is wrong. Low brake pads would result in a warning clip squeal or tire pad sensor light illumination. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 59

Technician A says the ABS systems control unit is programmed to ignore speed sensor inputs variations below a certain threshold. Technician B says a one-channel ABS system controls the hydraulic pressure to the rear brakes on both sides of the vehicle at the same time. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 59

Answer A is wrong. Minor variations in speed sensor input are not acted upon by the system. Answer B is wrong. These systems use one sensor to control the two rear wheels. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 60

Technician A says a leaking master cylinders primary piston seal may leak externally and can contaminate or damage the brake booster. Technician B says an over adjusted brake pedal may block the compensating port. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 60

Answer A is wrong. The primary pistons cup seals may leak externally and can damage the brake booster. Answer B is wrong. Blocking the compensating port can lead to pressure buildup and brake lockup. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 61

A vehicle has a hard pedal with little stopping power. Technician A says this could be the vacuum power brake booster. Technician B says a vacuum booster needs at least 10 Hg of vacuum to operate properly. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 61

Answer A is correct. An inoperative brake booster will result in a hard brake pedal. Answer B is wrong. A brake booster needs more vacuum, between 17-21 Hg of vacuum to function properly. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 62

The brake pad wear indicator light is illuminated on the instrument panel. Technician A says this is because the brake pads have become contaminated. Technician B says this is likely the pad wear sensor tip contacting the rotor. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 62

Answer A is wrong. This is usually caused by the sensors tip touching the rotor. If the brake pads have become contaminated the pads must be replaced. Answer B is correct. When the sensors tip contacts the rotor the pad warning sensor and related components light the pad warning indicator on the instrument panel. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 63

A vehicle with ABS anti-lock brakes has an audible clicking noise when it is first started. The noise goes away after a few seconds. Technician A says this sounds like one of the hydraulic valves in the ABS hydraulic valve assembly may be sticking. Technician B says this is a normal condition. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 63

Answer A is wrong. This is a normal condition. Answer B is correct. The ABS system runs a system check when the key is first turned to the ON position. The valves sometimes make a clicking noise during this check. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 64

Technician A says to adjust a height sensing proportioning valve while on the lift. Technician B says to adjust a height sensing proportioning valve at vehicle curb ride height. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 64

Answer A is wrong. Adjusting a height sensing proportioning valve on the lift would reduce hydraulic pressure to the rear brakes. Answer B is correct. Adjust a height sensing proportioning valve at curb height with all four tires firm on the ground. Adjusting this type of proportioning valve on a lift would reduce rear brake performance. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 65

Two technicians are discussing master cylinder residual check valves. Technician A says the check valve is used on four wheel disc brake systems. Technician B says the valve maintains pressure when the brakes are released. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 65

Answer A is wrong. The residual check valve is used on vehicles with drum brakes. Answer B is correct. The constant low pressure, usually 6 psi to 8 psi keeps air from entering the wheel cylinders. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 66

Technician A says accumulators are found only on non-integral ABS systems. Technician B says the some integral ABS units contain an electric pump and the accumulator must be discharged before repair. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 66

Answer A is wrong. High pressure gas charged accumulators are used with integral ABS systems. Low pressure spring loaded accumulators are sometimes used on non-integral ABS systems. Answer B is correct. They often use electric pumps to build pressure. These accumulators are under pressure and manufacturers discharging procedures must be followed before performing repairs. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 67

Technician A says passive permanent magnet ABS wheel speed sensors produce AC voltage. Technician B says input from wheel speed sensors are used for anti-lock brake systems, electronic traction control, and electronic stability control. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 67

Answer A is wrong. The signal is sent to the electronic controller for traction control. Answer B is wrong. The signal is sent to the electronic controller for (ABS) anti-lock brake, (TCS) traction control system, and (ESC) electronic stability control. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 68

A vehicle's right front wheel has a growl that increases with vehicle speed. The most likely cause is: A. Excessive rotor lateral run out. B. Warped rear brake drums. C. Worn CV-Joint. D. Worn wheel bearing.

Answer 68

Answer A is wrong. Excessive lateral rotor run-out will result in a pulsating feeling in the brake pedal (front) or the drivers seat (rear). Answer B is wrong. A warded brake drum is similar to a warped rotor and will result in a pulsating feeling in the brake pedal (front) or the drivers seat (rear). Answer C is wrong. A worn CV- Joint will produce a clacking noise while cornering. Answer D is correct. A worn out wheel bearing will cause a growl that increases with vehicle speed.

Question 69

Two technicians are discussing traction control systems. Technician A says if the amber TCS light flashes while driving there is an electrical fault in the system. Technician B says these systems require an electric pump and accumulator. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 69

Answer A is wrong. In most systems this is a normal response to road conditions and there is nothing for the customer to be concerned about. It indicates that the system is activated and restoring traction to the slippery road surface. Answer B is correct. They use an electric pump and accumulator to apply the wheel brake on the wheel that has lost its traction. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 70

The front brake pads on a vehicle with a quick take up master cylinder need replacement. They were replaced just recently. Technician A says this is a low drag brake system. Technician B says this could be caused by a sticking quick take up valve. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 70

Answer A is correct. Both technicians are correct. This type of master cylinder is used with low drag brake calipers. It is distinguishable by a large diameter piston and primary low pressure bore located at the back or push rod end of the master cylinder. Answer B is wrong. Both technicians are correct. The quick take up master cylinder provides more brake fluid volume to take up the additional space between the pads and the rotor. They are fuel efficient. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 71

Technician A says electronic stability control systems require four wheel speed sensors. Technician B says the telltale lamp will flash when the ESC system is activated. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 71

Answer A is wrong. These systems must be able to apply all four wheels individually. The vehicle is usually equipped with a four channel ABS system with a wheel sensor dedicated to each wheel. Answer B is wrong. The telltale lamp will flash when the system is active and will turn off when stability is regained. It will stay on if a malfunction exists. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 72

Which of these is not part of an integral ABS unit. A. Hydraulic booster B. Master Cylinder C. Hydraulic Modulator D. Vacuum Booster

Answer 72

Answer A is wrong. The hydraulic booster is part of an integrated or integral ABS system. Answer B is wrong. The master cylinder is part of in integrated or integral ABS system. Answer C is wrong. The hydraulic booster is part of in integrated or integral ABS system. Answer D is correct. The vacuum booster is not part of in integrated or integral ABS system.

Question 73

The left front inner most pad on a four wheel disk brake vehicle is excessively worn. Which if these is most likely the cause. A. Proportioning valve. B. Metering valve. C. Brake caliper slide pins. D. Sticking caliper piston.

Answer 73

Answer A is wrong. The proportioning valve is controls brake pressure to the rear brakes to prevent wheel lockup. Answer B is wrong. The metering valve is provides braking balance. Answer C is correct. Sticking brake caliper slide pins will result in inboard pad wear. Answer D is wrong. A sticking caliper piston results in little or no operation of that brake unit. This would result in a pull to the opposite side when braking and little movement of the inside pad mentioned.

Question 74

A vehicle suffers from uneven pad wear. Technician A says to check for sticking slide pins. Technician B says this could be caused by a sticking caliper piston. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 74

Answer A is wrong. Sticking slide pins will result in uneven pad wear. Answer B is wrong. A sticking caliper piston can result in uneven and excessive pad wear. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 75

Which of the following brake fluids are silicone based: A. Dot 2 B. Dot 3 C. Dot 4 D. Dot 5

Answer 75

Answer A is wrong. Only Dot 5 is silicon based. Answer B is wrong. Only Dot 5 is silicon based. Answer C is wrong. Only Dot 5 is silicon based. Answer D is correct. Dot 5 brake fluid is silicon based.

Question 76

A vehicles brake pedal fades to the floor board at stop lights. Technician A says it may be low vacuum to the vacuum assist brake booster. Technician B says it is likely to be the master cylinder. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 76

Answer A is wrong. Low brake booster vacuum leaves a vehicle with a hard brake pedal. Answer B is correct. A master cylinder can have an internal leak (seals) or an external leak causing the pedal to fade to the floor. Do a complete visual inspection first. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 77

Two technicians are inspecting a brake drum for wear. Technician A says if the brake drum has small cracks along it's inside lining it should be replaced. Technician B says if a brake drum has minor pitting along it's inside lining it may be resurfaced. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 77

Answer A is wrong. When a brake drum has cracks it must be replaced. Answer B is wrong. When a drum shows signs of pitting and heat scoring, it may be resurfaced. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 78

Technician A says the primary shoe faces the front of the vehicle. Technician B says the lining of the primary shoe must be riveted to the shoe plate. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 78

Answer A is correct. Also the primary shoe typically has a shorter lining than the secondary. Answer B is wrong. Brake shoe manufacturers will also use glue to bond the lining to the shoe. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 79

Technician A says double flare copper tubing is used for brake lines. Technician B says double flare steel tubing is used for brake lines. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 79

Answer A is wrong. Copper tubing is not used in brake systems. Answer B is correct. Double flare not single flare steel tubing is used in brakes systems. Answer C is wrong. Technician B is correct. Answer D is wrong. Technician B is correct.

Question 80

The left front brake of a four wheel disc brake system is dragging. Technician A says this could be caused by a restriction in the brake line. Technician B says this could be caused by broken return springs. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 80

Answer A is correct. A kink or restriction in the brake line will allow fluid to apply the brake unit but not allow fluid to return to the master cylinder leaving the brake applied. Answer B is wrong. Broken return springs would cause drag on a front disc/rear drum type brake system. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 81

A vibration is felt in the steering wheel only while braking. Technician A says excessive lateral runout on the front rotors will result in this condition. Technician B says to use a dial indicator to check lateral runout. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 81

Answer A is wrong. A vibration in the steering wheel indicates a problem with the front rotors and a vibration in the seat the rears. Answer B is wrong. A dial indicator is used to check lateral runout. Lateral runout can be caused by unevenly and excessively torqued lug nuts or studs, or a burr or rust between the hub and rotor. Answer C is correct. Both technicians are correct. Answer D is wrong. The correct answer is C.

Question 82

A three-function combination valve has all of these except: A. Proportioning valve B. Metering valve C. Solenoid valve D. Brake failure light switch

Answer 82

Answer A is wrong. The proportioning valve is part of the combination valve. Answer B is wrong. The metering valve is part of the combination valve. Answer C is correct. The solenoid valve is not part of the combination valve. Answer D is wrong. The brake failure light switch is part of the combination valve.

Question 83

A hydro-boost brake system has reduced braking performance. Technician A says to check the power steering system. Technician B says to check the vacuum check valve. Who is correct? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 83

Answer A is correct. The power steering pump produces pressure for the Hydro-Boost unit. Answer B is wrong. A vacuum check valve is used on a vacuum power booster. Answer C is wrong. Technician A is correct. Answer D is wrong. Technician A is correct.

Question 84

On a car with disc/drum brakes, the front brakes grab quickly when light pedal pressure is applied. This problem could be caused by a bad: A. Proportioning valve B. Pressure safely switch C. Metering valve D. Residual check valve

Answer 84

The correct answer is C. The metering valve delays the flow of brake fluid to the front calipers until the pressure in the system rises to a point where the wheel cylinder can overcome the tension of the brake shoe return springs. The purpose is to have both front and rear brakes apply simultaneously. This prevents the front brakes from locking up during light brake applications.

Question 85

The driver of a vehicle with power disc/drum brakes says that the brake pedal moves slowly to the floor while maintaining pedal pressure at a stoplight. What could cause this problem? A. Leaking primary piston cup in master cylinder B. Leaking power brake booster C. Leaking residual check valve in master cylinder D. Internal leak in the combination valve

Answer 85

The correct answer is A. If the primary piston cup in the master cylinder is leaking, pressure will not build up ahead of the primary piston to increase pressure to the rear brakes. The piston will then move forward until the spring is compressed enough to move the secondary piston. Consequently, this internal leak will cause the brake pedal to slowly drop to the floor.

Question 86

What is the purpose of the master cylinder residual check valve(s) on vehicles equipped with drum brakes? A. Allows the driver to pump up the brakes B. Prevents air from entering the hydraulic system C. Prevents wheel lockup by reducing the hydraulic pressure D. Reduces pedal pulsation by controlling hydraulic pressure

Answer 86

The correct answer is B. Residual check valve(s) are used on drum brakes to keep residual low pressure (slight static pressure) in the brake system at all times even when the brake pedal is released. This pressure (5-20psi) keeps the lips of the wheel cylinder piston cups tight against the cylinder walls to prevent air from entering the system when at rest (brakes released).

Question 87

A technician has just overhauled the front brakes on a vehicle with front disc and rear drum brakes. However, when he attaches a pressure bleeder (pressurized to about 25 psi) to the master cylinder, he cannot get any fluid to come out of the disc brake caliper bleeder screws. Which of the following is MOST LIKELY the cause? A. Bad proportioning valve B. Bad pressure differential valve C. Proportioning valve release button not activated D. Metering valve release button not activated

Answer 87

The correct answer is D. A metering valve requires a minimum pressure (typically between 75-125 psi) to open. At this point pressurized fluid flows to the front calipers. Since the bleeder tank is only pressurized to 25 psi, fluid pressure is too low to open the metering valve during this procedure. Therefore, when you use a pressure bleeder on a system with a metering valve, you must manually keep the valve open by either pushing the button in on the end of the valve, or pulling the stem outward on the end of the valve.

Question 88

On a vehicle with single piston floating caliper front disc brakes, the brakes pads on the left side of the vehicle are almost completely worn while the right side is almost new. Technician A says that too much rotor runout could be the cause. Technician B says that a binding caliper piston could be the cause. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 88

The correct answer is B. Excessive rotor runout would cause a pulsating brake pedal, but not uneven side-to-side pad wear. A frozen caliper piston on the other hand, will keep both inner and outer brake pads equally applied against the rotor even when the brake pedal is released. This constant friction will cause rapid pad wear in the affected caliper as well as a front-end pull.

Question 89

A hydraulic brake line is leaking. Which of the following is the correct repair procedure? A. Cut out the bad section and replace with new steel tubing using compression fittings. B. Replace the leaking line with double-flared, seamless copper tubing. C. Cut out the bad section and replace with single-flared steel tubing using flare nuts and unions. D. Replace the leaking line with double-flared steel tubing.

Answer 89

The correct answer is D. Steel tubing of the same size, type, and length with double flared ends must be used when replacing a traditional SAE double inverted flare style hydraulic brake line.

Question 90

Which of the following problems would be caused by using a residual check valve in a disc brake master cylinder? A. Reduced brake pedal travel B. Reduced brake system pressure C. Increased brake pad wear D. Increased rotor runout

Answer 90

The correct answer is C. If a residual check valve was installed in a disc brake master cylinder, it would cause increased brake pad wear since the residual brake pressure would cause the caliper pistons to keep the pads applied even when the brake pedal is released.

Question 91

A customer complains that their vehicle pulls to the right when the brakes are applied. Technician A says a restricted brake line to the left caliper can cause this problem. Technician B a malfunctioning proportioning valve is probably the cause. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 91

The correct answer is A. A restriction in the brake line will cause a drop in fluid pressure to the affected caliper. This will cause the caliper to be unable to exert the same force against the pads as the unrestricted side. Because of this, the vehicle will pull to the side where the pressure is highest and brake force is greatest. In this case, that would be the right side.

Question 92

With foot pressure applied, the brake pedal on a vehicle with vacuum assisted power brakes moves down slightly when the engine is started. Technician A says that this condition can be caused by a leaking power brake booster diaphragm. Technician b says that the cause could be a faulty power brake booster check valve. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 92

The correct answer is D, neither technician is right. With the brake pedal applied while starting the engine, the pedal should move down slightly indicating that the vacuum booster is operating properly.

Question 93

The hydraulic system on a vehicle with integral ABS is to be bled. Technician A says that the front brakes can be bled in a conventional manner. Technician B says that both front and rear brakes can only be bled using the pressure from a fully charged accumulator. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 93

The correct answer is A. The front hydraulic circuits in an integral ABS system can be bled in the conventional manner since it is the booster piston in the hydraulic modulator assembly that supplies fluid to the front brakes. However, the rear circuit is dependent upon boost pressure from the accumulator, which means the accumulator must be fully charged in order to bleed the rear brakes.

Question 94

A driver complains that ABS system on his car engages every time he applies the brakes on a cobblestone roadway he uses going back-and-forth to work. This condition means that: A. The system is operating normally. B. The wheels are traveling at different speeds. C. A wheel speed sensor(s) is faulty. D. Both A and B

Answer 94

The correct answer is D. When a vehicle with ABS is braked on abnormally irregular road surfaces, like a cobblestone road, the wheels decelerate at different speeds. Because the signals coming from the wheel speed sensors under this condition are not in sync with each other, the ABS control unit interprets this as impending wheel lockup and responds by engaging the system.

Question 95

Two technicians are discussing the duo-servo type drum brake design. Technician A says the brake lining on the secondary shoe is usually longer and thicker than the brake lining on the primary shoe. Technician B says the primary shoe is installed toward the rear of the vehicle. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 95

The correct answer is A. In a duo-servo drum brake design under normal forward braking, the friction developed by the secondary lining is greater than the primary lining. Therefore, the secondary shoe is typically longer and thicker than the primary shoe. The primary shoe is installed facing the direction of forward motion.

Question 96

All of the following statements about leading-trailing type drum brakes are true EXCEPT: A. The leading shoe does most of the forward braking. B. Both brake shoes are held against a fixed anchor on the backing plate. C. They are self-energizing. D. The trailing shoe does most of the reverse braking.

Answer 96

The correct answer is C. The leading-trailing drum brake design is not self-energizing. This is due to the fixed anchor on the backing plate, which prevents the shoes from transferring their force to one another.

Question 97

Technician A says that DOT 5 brake fluid has a lower boiling point than DOT 4. Technician B says that DOT 4 brake fluid is silicone-based and should never be used in an ABS system. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 97

The correct answer is D, neither technician is right. It is DOT 4 brake fluid that has a lower boiling point, and DOT 5 that is silicone-based and should not be used in any ABS system.

Question 98

Brakes that drag or fail to release can be caused by which of the following conditions in the master cylinder? A. Leaking primary cup B. Leaking secondary cup C. Failure of the residual pressure check valve D. Clogged compensating port

Answer 98

The correct answer is D. The compensating port allows for residual hydraulic line pressure to be discharged into the reservoir as the brake pedal is released. A clogged or restricted compensating port will create a pressure build-up, which will cause the brakes to drag or fail to release. The port can be clogged by foreign matter, blocked by a swollen primary cup or covered by the primary cup if the master cylinder pushrods is improperly adjusted.

Question 99

All of the following could cause a hard brake pedal on a vehicle with power brakes EXCEPT: A. An engine with the valves adjusted too tight B. Brake fluid on the linings C. A leak in the brake hydraulic system D. A frozen caliper

Answer 99

The correct answer is C. A leak in the hydraulic system wouldn't cause a hard pedal, but rather create the exact opposite condition due to the hydraulic pressure loss. An engine with the valves adjusted too tight would develop low vacuum. This would adversely affect the operation of the power brake booster and cause a hard pedal. Brake fluid on the lining will cause the friction material to grab resulting in a hard pedal, while a frozen caliper would prevent retraction of the piston resulting in a similar condition.

Question 100

Technician A says that a caliper seal installed in the caliper bore is called a stroking seal. Technician B says that when the brake pedal is released, the piston in the caliper moves back in its bore due to the action of the piston seal. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 100

The correct answer is B. The outward movement of the caliper piston during brake application causes the piston seal to distort. Once the brakes are released however, the seal returns to its original shape forcing the piston to retract in its bore. A caliper seal that is installed on the piston is known as a stroking seal.

Question 101

When replacing disc brake pads, you must bottom the caliper piston in its bore to create room for the new pads. Which of the following is the proper procedure? A. Use a C-clamp or pliers to slowly bottom the piston in the caliper. B. Remove half the fluid from the master cylinder reservoir, then use a C-clamp or pliers to slowly bottom the piston in the caliper. C. Connect a hose to the caliper bleeder screw and insert the other end of the hose into a suitable container, open the bleeder screw, then use a C-clamp or pliers to slowly bottom the piston in the caliper. D. Remove the caliper from the vehicle, then use a C-clamp or pliers to slowly bottom the piston in the caliper.

Answer 101

The correct answer is C. By opening the bleeder screw on the caliper, contaminated fluid is not forced back into the master cylinder (or on ABS vehicles, into the hydraulic control unit). Answer B is wrong because, while it will work, doing so can cause problems in the hydraulic system. Answer A is wrong because, without checking the fluid level or opening the bleeder screw, fluid could be forced into and spill out of the master cylinder reservoir. Answer D is wrong because caliper removal is not necessary.

Question 102

Technician A says that all 3-channel ABS systems use only 3 wheel speed sensors. Technician B says that a 4-channel ABS system means that fluid pressure is independently regulated to each of the wheels during an ABS stop. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 102

The correct answer is B. The number of wheel speed sensors used on an ABS system does not necessarily indicate the number do channels the system has. A channel is an independently controlled fluid path from the hydraulic modulator to the wheel. Therefore, a 3-channel system on a car can have a wheel speed sensor at each wheel, even though there are only 3 individually controlled hydraulic circuits: two in the front, and one in the rear.

Question 103

Technician A says that when a rotor is machined, an equal amount of material must always be removed from both sides. Technician B says that the minimum thickness dimension cast into the rotor is the dimension that the rotor can be machined to. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 103

The correct answer is D, neither technician is right. The minimum thickness dimension cast into the rotor is usually the discard dimension. The rotor should not be machined closer than 0.030-in. to this dimension in order to allow for wear. When machining a rotor, you do not have to remove an equal amount of material from both sides if the vehicle has floating or sliding calipers. However, on fixed calipers an equal amount must be machined form both sides.

Question 104

The purpose of an anti-lock brake system is to maintain tire (wheel) slip at what level? A. A level between 50-75% B. 100% C. 0% D. A level between 10-20%

Answer 104

The correct answer is D. | Maximum braking effectiveness is achieved when tire slip is maintained at a level between 10-20%.

Question 105

While on a road test, a technician notices that the rear wheels lockup and the car skids when attempting to stop quickly from high speed. The MOST LIKELY cause of this problem is a defective: A. Residual pressure check valve B. Pressure differential valve C. Metering valve D. Proportioning valve

Answer 105

The correct answer is D. The proportioning valve reduces the pressure applied to the rear wheel cylinders in relation to the pressure applied to the front calipers under heavy braking. A defective proportioning valve can cause the rear wheels to lock and skid during sudden stops because the fluid pressure to the rear wheel cylinders would be unregulated.

Question 106

Excessive slack in the parking brake cables can be eliminated on most vehicles by making an adjustment at the: A. Equalizer B. Star wheel adjusters C. Strut rod D. Pushrod

Answer 106

The correct answer is A. On most vehicles, parking brake adjustment consists of shortening the length of one or more cables to remove excessive slack. This adjustment is generally made by tightening an adjusting nut at the equalizer.

Question 107

A customer complains that the brake warning light comes on whenever the brake pedal is depressed while driving. All of the following could cause this to occur EXCEPT: A. A leak in the rear half of the hydraulic system B. A short to ground in the warning light circuit C. A leak in the front half of the hydraulic circuit D. A leaking pressure differential switch

Answer 107

The correct answer is B. Any leak in the hydraulic system that causes unequal pressure to be applied to one side of the pressure differential piston will cause the warning light to illuminate. The only choice here is a short to ground in the light. This failure would cause the light to stay on all the time regardless of hydraulic condition.

Question 108

The MOST common cause for premature front brake pad wear in a disc/drum system is: A. Seized calipers B. Faulty master cylinder C. Improperly adjusted rear shoes D. Malfunctioning metering valve

Answer 108

The correct answer is C. While all of the choices listed could cause the pads to wear prematurely, the most common cause of this condition is when the rear shoes are incorrectly adjusted. Since the majority of braking action is done by the front brakes (especially on front-wheel-drive cars), it is imperative that the rear shoes are adjusted properly. This will help balance brake action as well as lining wear.

Question 109

Technician A says that DTCs can be accessed from any ABS system using flash diagnostics. Technician B says that ABS system tests can be performed with a bidirectional scan tool. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 109

The correct answer is B. Only a few ABS systems (primary RWAL) offer flash code diagnostics for retrieving stored fault codes. A bi-directional scan tool can be used to perform tests on ABS system components. A technician can activate solenoids and valves while observing the change in that circuit.

Question 110

To determine if an intermittent ABS problem is related to an erratic wheel speed sensor signal, which of the following should be used? A. Ohmmeter B. Voltmeter C. Scan tool D. Digital storage oscilloscope

Answer 110

The correct answer is D. Answers B and C are incorrect because the sampling rates are too low. An intermittent can be seen with the digital storage oscilloscope (DSO) because it samples the electrical signal over 250,000 times per second.

Question 111

A few minutes after the engine was turned off on a vehicle with vacuum power assist, the brake pedal is applied and it is hard to push. Technician A says that this is normal condition. Technician B says that the booster check valve is leaking. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 111

The correct answer is B. Technician A is incorrect because there should be at least one power assist before the pedal gets hard to push. Technician B is correct because the lack of power assist indicates that the check valve is leaking.

Question 112

During a brake inspection, an area of the vacuum brake booster below the master cylinder is found to be damp. Technician A says that this is a normal condition. Technician B says that any evidence of fluid indicates a leak and the master cylinder must be replaced. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 112

The correct answer is A. A small amount of fluid present here is normal due to the lubricating action of the master cylinder bore end seal. The brake fluid is kept from leaking back into the power booster by a seal on the pushrods. If a large amount of fluid is present, unbolt the master cylinder from the booster and look for signs of leakage.

Question 113

Technician A says that tapered roller bearing can be adjusted using a torque wrench. Technician B says that tapered roller bearings are adjusted using a dial indicator. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 113

The correct answer is C, both technicians are right. Both methods are commonly used to adjust tapered roller bearings. Consult the vehicle service manual for the specific adjustment procedure.

Question 114

All of the following could cause a pulsation to be felt in the brake pedal EXCEPT: A. Brake drum out of round B. Normal ABS operation C. Lateral rotor runout D. Seized caliper piston

Answer 114

The correct answer is D. A seized caliper piston can cause a brake pull or a hard pedal, but it would not cause a pedal pulsation. All of the other choices can cause a pulsation to be felt through the brake pedal.

Question 115

Technician A says that, when testing a proportioning valve, the pressure at the outlet port to the rear brakes should rise at a faster rate, once transition pressure is reached. Technician B says that vehicles with diagonally-spilt hydraulic systems must have the proportioning valve tested twice. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 115

The correct answer is B. Vehicles with diagonally-split hydraulic systems have dual proportioning valves, so if a problem is suspected, both valves must be tested. Technician A is incorrect because, when testing a proportioning valve, the pressure at the outlet to the rear brakes will rise at a slower rate, once transition pressure is reached.

Question 116

All of the following disc brake rotor measurements can be performed using a micrometer EXCEPT: A. Parallelism B. Thickness C. Runout D. Taper

Answer 116

The correct answer is C. | Lateral runout is measured using a dial indicator. All of the other measurements can be made using a micrometer.

Question 117

Which of the following disc brake caliper designs usually allow the brake pads to be removed without removing the caliper? A. Fixed B. Floating C. Sliding D. All of the above

Answer 117

The correct answer is A. The disc brake pads can be usually be removed from fixed caliper while the caliper is mounted in the place. Floating and sliding calipers require that the caliper be removed or pivoted out of the way to access the disc brake pads.

Question 118

After applying the brake pedal several times to deplete the fluid reserve in the accumulator do a Hydro-Boost system, a technician applies the brake pedal with moderate pressure and starts the engine. What should the technician feel at the pedal if the Hydro-Boost system is operating properly? A. The pedal should initially rise before moving downward. B. The pedal should initially move downward before rising up. C. The pedal should be move downward. D. The pedal should rise.

Answer 118

The correct answer is B. If the Hydro-Boost system is operating properly, the brake pedal should initially move downward before rising up against foot pressure.

Question 119

All of the following can cause disc brake squeal EXCEPT: A. Loose or missing anti-rattle springs B. Grease on the linings C. Glazed linings D. Dirt embedded in the linings

Answer 119

The correct answer is B. Brake linings that are contaminated with grease, oil or brake fluid can cause the vehicle to pull when the brakes are applied, but would not cause brake squeal.

Question 120

Technician A says that when rebuilding a caliper with a stroking seal, the condition of the bore surface is critical. Technician B says that when rebuilding a caliper with a fixed seal, the condition of the piston surface is the most important consideration. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or D

Answer 120

The correct answer is C, both technicians are right. A stroking seal is located in a groove in the caliper piston and moves with the piston. The lip of the seal rides against the surface of the caliper bore, so the caliper bore must be smooth to prevent leaks. A fixed seal is installed in a groove in the caliper bore. It seals against the outside surface of the caliper piston, so that surface must be in good condition to provide a good seal.

Question 121

All of the following can cause a vehicle to pull to one side when the brakes are applied EXCEPT: A. Seized caliper piston B. Worn strut rod bushing C. Blocked master cylinder compensating port D. Brake fluid soaked linings

Answer 121

The correct answer is C. A blocked master cylinder compensating port could cause all brakes to drag but would not cause a brake pull. All of the other choices could cause brake pull.

Question 122

Technician A says that ABS wheel speed sensor gap should be adjusted with a non-magnetic feeler gauge. Technician B says that a paper spacer can be used to adjust ABS wheel speed sensor gap but the paper must be removed before the vehicle is operated. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 122

The correct answer is A. New wheel speed sensors come with the paper spacer installed but it is not necessary to remove it; the spacer is designed to wear off during vehicle operation.

Question 123

When discussing wheel bearings, all of the following statements are true EXCEPT: A. Tapered wheel bearings are most commonly used on drive axles. B. Sealed ball bearings are not adjustable. C. A new grease seal should be installed when bearings are repacked. D. The races on tapered wheel bearings cannot be interchanged.

Answer 123

The correct answer is A. | Tapered roller bearings are usually used on non-drive axles. All of the other statements are true.

Question 124

All of the following could cause the parking brake to not hold a vehicle on a grade EXCEPT: A. Seized cables B. Excessive rear brakes shoe-to-drum clearance C. Seized wheel cylinder D. Broken parking brake linkage

Answer 124

The correct answer is C. The parking brake system engages the rear brakes mechanically; a seized wheel cylinder would not affect parking brake operation.

Question 125

To determine the serviceability of a brake drum, all of the following should be checked EXCEPT: A. Diameter B. Minimum thickness C. Out-of-roundness D. Taper wear

Answer 125

The correct answer is B. Minimum thickness is checked when inspecting a disc brake rotor. All of the other measurements mentioned should be made when inspecting a brake drum.

Question 126

A vehicle's brake pedal is pumped rapidly 20 times and then held down. The master cylinder cover is then removed and when the pedal is released, a geyser is seen coming from the reservoir. Technician A says that this indicates that air is trapped in the system. Technician B says that this means that fluid is being forced out of the cylinder bore through the compensating ports and is normal master cylinder operation. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 126

The correct answer is A. Pumping the brakes compresses the air and when the pedal is released, the compressed air pushes the hydraulic fluid back through the lines, causing it to squirt. Technician B is wrong because a small squirt of fluid should appear over the reservoir, indicating that fluid is being forced out of the cylinder bore through the compensating ports, only when the pedal is applied.

Question 127

Technician A says that RWAL ABS systems must be diagnosed using a scan tool. Technician B says that the ABS warning light will only come on when there is a fault in the system. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 127

The correct answer is D, neither technician is right. Technician A is wrong because, while most Rear Wheel Anti-Lock (RWAL) systems offer flash-code diagnostics, most four-wheel ABS systems require the use a of a scan tool to extract stored fault codes from the computer's memory. Technician B is wrong because the 'anti-lock' warning light will come on whenever the key is turned ON, and if there are no faults in the system, will then go out after a few seconds.

Question 128

Technician A says that any imperfection found in a phenolic caliper piston warrants replacement. Technician B says that a phenolic caliper piston should be protected with a block of wood when installing it into the caliper bore with a C-clamp. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 128

The correct answer is B. A phenolic piston should be protected to keep it from being damaged when a C-clamp is used. Technician A is wrong because minor surface imperfection are OK provided they do not enter the dust boot groove area.

Question 129

Which of the following should be used to measure the thickness of a scored rotor? A. Vernier caliper B. Outside micrometer with flat anvil and spindle C. Inside micrometer D. Outside micrometer with pointed anvil and spindle

Answer 129

The correct answer is D. An outside micrometer with a pointed anvil and spindle is a disc brake micrometer. Unlike a standard micrometer that uses a flat surface on the anvil and spindle, a disc brake micrometer uses pointed tips so the instrument can fit into the grooves of scored rotors, to accurately measure the thickness.

Question 130

During routine vehicle maintenance, the fluid level in the master cylinder reservoir is checked. When the reservoir cap is removed, purple colored fluid is found in the reservoir. Technician A says that this means the fluid should be topped off with DOT 4, which has a higher boiling point than regular brake fluid. Technician B says that this means that the fluid is contaminated; all rubber parts in the system must be replaced and the system flushed. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 130

The correct answer is D, neither technician is right. | Purple is the color of silicone fluid, and only DOT 5 fluid should be used to top off the reservoir.

Question 131

A complete front brake service has just been performed on a vehicle with disc brakes: rotors turned, calipers rebuilt, new brake pads, bearings repacked and adjusted. However, when the vehicle is road tested, a pulsation can be felt through the pedal. Which of the following is the MOST LIKELY cause of the pulsation? A. Non-directional finish not applied to rotors B. Wrong linings compound chosen C. Over-torqued lug nuts D. Incorrect bleeding sequence

Answer 131

The correct answer is C. Over-tightening the lug nuts can distort the rotor and create excessive runout, resulting in a pedal pulsation. All of the other choices may cause other problems, but not a pedal pulsation.

Question 132

Brake fluid leaking from a cracked brake line causes the brake light on the dashboard to come on in response to the loss of hydraulic pressure. Which of the following valves in the hydraulic system switched on the light? A. Metering valve B. Pressure differential valve C. Proportioning valve D. Residual check valve

Answer 132

The correct answer is B. The pressure differential valve and warning switch alerts the driver of a pressure loss in one of the hydraulic circuits. The residual check valve is often used in the master cylinder outlet port of drum brake systems in order to maintain a slight pressure in the brake lines and wheel cylinders, which keeps wheel cylinder pistons tight against their bores. The metering valve delays front disc brake operation until the rear brakes shoes overcome the return spring tension. The proportioning valve is used to control rear brakes pressures, particularly during hard stops.

Question 133

Technician A says that an integral ABS system is an add-on system. Technician B says that a non-integral ABS system is a high-pressure system. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 133

The correct answer is D, neither technician is right. The non-integral ABS system is added on to the vehicle's existing hydraulic brake system, and is generally a low-pressure arrangement.

Question 134

The diameter of drums mounted on the same axle should measure within how many thousands of an inch of one another? A. 0.001 B. 0.005 C. 0.010 D. 0.020

Answer 134

The correct answer is C. | The diameter of brake drums mounted on the same axle must be within 0.010-in. of one another.

Question 135

Absorption of 3% moisture can reduce the boiling point of DOT 3 brake fluid by what percentage? A. 10% B. 20% C. 25% D. 50%

Answer 135

The correct answer is C. | Absorption of 3% moisture can reduce the boiling point of DOT 3 brake fluid by 25%.

Question 136

All of the following are procedures for removing air from a hydraulic system EXCEPT: A. Bench bleeding B. Power bleeding C. Manual bleeding D. Vacuum bleeding

Answer 136

The correct answer is A. Bench bleeding is a procedure for removing air from the master cylinder only. All of the other procedures remove air from the entire system.

Question 137

All of the following can be used to apply a non-directional finish to a disc brake rotor EXCEPT: A. Sanding block B. Fine file C. Lathe attachment D. Sanding disc

Answer 137

The correct answer is B. Files are not used to apply a non-directional finish on a disc brake rotor. All of the others methods can be used to give the rotor a swirl-like finish.

Question 138

All of the following can cause a problem in the Hydro-Boost system EXCEPT: A. Loose power steering pump belt B. Leaking power steering hoses C. Low power steering pump pressure D. Leaking check valve

Answer 138

The correct answer is D. A vacuum check valve is used on a vacuum power booster. The Hydro-Boost system uses power steering pump fluid pressure rather than intake manifold vacuum, so all of the other choices would apply.

Question 139

A customer says that he has just replaced his front disc brake pads himself and now the ABS warning light is on. Which of the following could be the cause? A. Damaged wheel speed sensor B. Incorrect wheel speed sensor gap C. Stuck ABS solenoid valve D. All of the above

Answer 139

The correct answer is D. Some common ABS problems can be caused by carelessness when performing basic brake service. Wheel speed sensors can be disturbed or damaged accidentally. Solenoid valves can stick if the caliper bleeder screws are not opened when the caliper pistons are retracted. Since the caliper is the lowest point in the system, dirt and corrosion naturally accumulate there. If the bleeder screws are not opened, brake fluid and these contaminants are forced backward into the system. When these contaminants find their way into the hydraulic control unit, they can cause valves to stick.

Question 140

Drum brake drag can be caused by all of the following EXCEPT: A. Frozen parking brake cables B. Frozen star wheel C. Restricted brake shoes D. Swelled wheel cylinder cups

Answer 140

The correct answer is B. A frozen star wheel would not cause brake drag. Rather, it would prevent the automatic adjuster mechanism from working, which would gradually cause the brake shoe-to-drum clearance to increase as the linings wore. All of the other answers could cause the brake shoes to not retract from the drum, resulting in brake drag.

Question 141

Technician A says the rear brake shoes should be properly adjusted before adjusting the parking brake. Technician B says the parking brake lever should be disengaged before adjusting the equalizer. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 141

The correct answer is A. The brake shoes must be correctly adjusted for the parking brake to work properly. There may not be enough adjustment in the parking brake system to overcome excessive shoe-to-drum clearance, resulting in the parking brake not being able to hold the vehicle in place when it is applied. Technician B is wrong because the parking brake lever must be engaged a certain number of clicks before the equalizer is adjusted.

Question 142

Which of the following should be used to clean a disc brake rotor after it is machined? A. Compressed air B. Solvent tank C. Soap and water D. Brake cleaning Solvent

Answer 142

The correct answer is C. When rotor resurfacing is completed, wash the rotor with soap and water and wipe it off with a clean shop towel. Brake cleaning solvent may not remove all of the fine particles left over from the machining process, and these can become imbedded in the new pads and cause brake noise.

Question 143

A front brake hose is being replaced. On this type of hose, the male end threads directly into the caliper. Technician A says the end of the hose that attaches to the steel brake line should be connected first. Technician B says that a new copper sealing washer should be used when the hose is connected to the caliper. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 143

The correct answer is B. Technician A is wrong because the male end of the hose should be connected and tightened first. If the female end of the hose is connected to the brake line first, the hose will twist when it is threaded into the caliper.

Question 144

Technician A says that surge bleeding is used in conjunction with manual or pressure bleeding. Technician B says that surge bleeding is used to remove air that is trapped in the brake hydraulic system. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 144

The correct answer is C, both technicians are right. Surge bleeding is a method of removing air from the hydraulic system that can be used when manual or pressure bleeding has proved inadequate. Surge bleeding churns the air in the wheel cylinder in order to loosen any pockets of air. However, the system should first be manually or pressure bled and again after surge bleeding to make sure all air has been expelled.

Question 145

All of the following are cause for brake rotor refinishing EXCEPT: A. Hard spots B. Heat checks C. Scoring D. Thickness variation

Answer 145

The correct answer is A. Hard spots call for rotor replacement, since resurfacing seldom removes the entire hard spot. All of the other conditions can be corrected by machining, provided it can be done without machining past the minimum rotor refinishing thickness.

Question 146

The front disc brake pads are being replaced on a vehicle with composite rotors. The left front rotor is scored below the 'machine to' but not the 'discard' thickness. The right front rotor has minor heat checks but otherwise checks out OK. If cast rotors are the only available replacements, which of the following is the proper course of action? A. Machine both rotors, being careful not to exceed the 'discard' thickness. B. Replace the left front rotor and machine the right front. C. Replaces both rotors. D. Replace the left front rotor and leave the right front alone.

Answer 146

The correct answer is C. Composite and cast rotors should not be mixed on the same axle. Answer A is wrong because, as the question indicated, the rotor is already worn past the 'machine to' dimension. Even if the rotor is not machined beyond the 'discard' thickness, this leaves no allowance for wear in the future.

Question 147

Which of the following brake symptoms can be caused by wheel bearing problems? A. Pedal pulsation B. Brake pull C. Grabbing D. All of the above

Answer 147

The correct answer is D. Loose wheel bearings can cause excessive rotor runout, which in turn can cause pedal pulsation. A failed wheel bearing seal can allow grease to contaminate the brake linings and cause brake pull and grabbing.

Question 148

Which component in the Hydro-Boost system provides power assist if there is a loss of hydraulic pressure to the system? A. Boost piston B. Check valve C. Accumulator D. Open-center spool valve

Answer 148

The correct answer is C. The accumulator can supply enough power assist for two stops if there is a loss of hydraulic pressure in the Hydro-Boost system. The boost piston provides the force to operate the master cylinder and the open-center spool valve regulates pump pressure. The check valve is used on vacuum operated boosters.

Question 149

A customer complains that the parking brake will not keep his car stationary. The car has four-wheel disc brakes. Technician A says the caliper levers could be out of adjustment. Technician B says the brake shoes could need adjustment. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 149

The correct answer is C, both technicians are right. The brakes must be inspected before reaching a diagnosis, but without knowing what type of system the car had, either technician could be right. There are two kinds of parking brakes on vehicles with rear disc brakes. One kind has small brake shoes inside a drum that is incorporated in the disc brake rotor. The shoes are forced against the drum by the linkage and cables in the same manner as conventional drum parking brakes. These shoes must be properly adjusted for the parking brake to work correctly. The other kind uses the rear disc brake pads. The linkage and cables actuate a cam or screw mechanism inside the caliper piston to push the caliper piston and pads against the rotor. Some of these systems require a caliper lever adjustment.

Question 150

When replacing an integral hub/bearing assembly on a front wheel drive vehicle, all of the following must be removed EXCEPT: A. Brake rotor B. Brake caliper C. Steering knuckle D. Wheel

Answer 150

The correct answer is C. The steering knuckle does not have to be removed when replacing an integral hub/bearing assembly. However, it must be removed when replacing the press-fit type front wheel bearing.

Question 151

A wheel cylinder has been disassembled and corrosion and light scoring have been found in the bore. Technician A says the bore can be refinished using a small hone lubricated with cutting oil. Technician B says oversize pistons and cup seals can be installed if the hone removes too much material. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 151

The correct answer is D, neither technician is right. Use only fresh clean brake fluid to lubricate the honing stones; never use petroleum-based cutting oil. After the cylinder has been honed, inspect it for excessive piston clearance. To check the maximum clearance, place a 0.003-inch feeler shim lengthwise in the cylinder bore. If the piston can be inserted with the shim in place, the cylinder is oversize and cannot be rebuilt.

Question 152

Two technicians are discussing traction control systems. Technician A says that some traction control strategies do not use the brakes control wheel spin. Technician B says that a fault in the ABS does not affect traction control. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 152

The correct answer is A. Some manufacturers reduce power to the spinning wheel by retarding the ignition timing, cutting off fuel injection to certain cylinders and/or mechanically closing the throttle, and may only apply the brakes if the wheel continues to spin. Technician B is wrong because the TCS uses the same components as the ABS; if there is a fault in the ABS the TCS is turned off as well.

Question 153

When rough machining a brake drum, the depth of cut and spindle feed rate should be: A. 0.010-0.015-in at high feed rate B. 0.010-0.015-in at low feed rate C. 0.005-in at high feed rate D. 0.005-in at low feed rate

Answer 153

The correct answer is A. The tool depth on a rough cut, where a large amount of material is removed to initially clean the drum, is usually about 0.010 - 0.015-in at a fast spindle feed rate.

Question 154

A technician wants to check the condition of a vehicle's brake fluid. Where should he get the sample to make the most accurate determination? A. Master cylinder reservoir B. Brake caliper C. Combination valve D. Wheel cylinder

Answer 154

The correct answer is B. The most accurate way to determine brake fluid condition is to take a sample from the vehicle's disc brake caliper, because the heat generated while stopping breaks down the corrosion inhibitors in the brake fluid.

Question 155

Two technicians are discussing brake bleeding procedures. Technician A says gravity bleeding is a relatively quickly way to bleed a brake system. Technician B says silicone brake fluid cannot be gravity bled. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 155

The correct answer is D, neither technician is right. Technician A is wrong because gravity bleeding is the easiest but most time consuming method of brake bleeding. Gravity bleeding relies on atmospheric pressure, acting on the surface of the fluid in the master cylinder, to force the fluid through the hydraulic system and out through the bleeders, which may take several hours. Technician B is wrong because gravity bleeding does not agitate the fluid and generate air bubbles, which is advantageous for systems with DOT 5 silicone fluid since it is prone to aeration.

Question 156

Which of the following is the MOST cost-efficient method of correcting excessive lateral runout on a disc brake rotor? A. Indexing B. Shimming C. Machining D. Replacement

Answer 156

The correct answer is A. Indexing involves moving the rotor position on the hub and rechecking the runout with a dial indicator. The number of wheel studs determines the number of possible positions to correct runout. This method requires little extra labor, no parts expense and no machining labor or expense. Resurfacing the rotor unnecessarily removes material and makes the rotor thinner, lessening its ability to absorb and dissipate heat and shortening the rotor's useable lifespan.

Question 157

New disc brake pads have just been installed. Technician A says the new pads must undergo a burnishing process during the road test to 'cure' the pads. Technician B says the new pads must be burnished to seat them on the rotor. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 157

The correct answer is C, both technicians are right. Whenever new brake pads are installed, they must undergo a burnishing, or break-in procedure before the vehicle can be operated normally. Burnishing accomplishes two things: It 'cures' the resin in the friction material, which could otherwise boil to the surface and cause glazing if the vehicle was immediately subjected to hard braking; and it ensures that the pads seat and make full contact with the rotor. The latter is particularly important if the rotors were not machined, since even a rotor that was deemed serviceable will not have a perfectly smooth surface.

Question 158

The parking brake pedal on a vehicle with automatic parking brake release remains depressed when the vehicle is placed in drive. All of the following are possible causes EXCEPT: A. Defective vacuum motor B. Faulty release switch C. Vacuum leak D. Seized cables

Answer 158

The correct answer is D. An automatic parking brake release mechanism releases the parking brakes when the automatic transmission is shifted into drive or reverse. These systems usually consist of a vacuum motor that is attached to a release lever and a vacuum switch that routes vacuum to the motor when the transmission is placed in drive or reverse. When the driver selects the drive or reverse position, the switch directs engine vacuum to the vacuum motor, which releases the lever and the parking brakes. Seized cables could keep the vehicle from moving or cause severe drag, but would not keep the pedal from returning to the unapplied position. All of the other possibilities listed could keep the release lever from releasing the pedal, causing it to remain in the applied position.

Question 159

Two technicians are discussing Electronic Stability Control (ECS) systems. Technician A says the ECS control module uses inputs from the steering wheel rotation sensor and wheel speed sensors to calculate the driver's intended path. Technician B says the ECS control module uses inputs from the lateral acceleration and yaw rate sensors to calculate the vehicle's actual path. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 159

``` The correct answer is C, both technicians are right. The ESC control program determines the driver's intentions using throttle and transmission data from the Powertrain Control Module (PCM), wheel speed rate from the wheel speed sensors and steering wheel position and rate of movement input from the steering wheel rotation sensor. It compares this information with the input from the lateral acceleration and yaw rate sensors to determine if correction is needed. If the actual path the vehicle is traveling does not match the intended path, the control module applies brake pressure to individual wheels and/or reduces engine power to correct the motion of the vehicle. ```

Question 160

A vehicle exhibits intermittent ABS activation, but when the technician connects a scan tool to the DLC, no DTCs are found. Which of the following could be the cause? A. Damaged tone wheel teeth B. Loose wheel bearing C. Rust under the wheel speed sensor mount D. All of the above

Answer 160

``` The correct answer is D. False ABS activation occurs when the ABS is engaged even though none of the wheels are slipping. The ABS control module can interpret a weak or erratic wheel speed sensor signal as wheel slip and cycle the ABS at the affected wheel. Rust under the sensor mount, loose wheel bearings and damaged tone wheel teeth can all affect the sensor gap, which in turn can cause a weak or erratic signal. ```

Question 161

Technician A says as brake fluid ages, it can corrodes ABS control valves. Technician B says brake fluid corrodes the copper in the brake lines. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 161

The correct answer is B. At a slow rate, over several months or years, brake fluid slowly corrodes the copper in the inner lining of the steel brake tubing. The copper leaches into the brake fluid as ions, atoms with an electrical charge. When the corrosion inhibitors in the brake fluid eventually deplete, these copper ions become the oxidizer that corrodes ferrous metal parts like ABS control valves. Technician A is wrong because it is not the brake fluid that corrodes the ABS control valves, but rather the copper ions that are released by the brake fluid.

Question 162

Which of the following is the MOST correct wheel cylinder repair procedure? A. Disassemble, loosen the bleeder screw, clean and hone, clean and assemble B. Disassemble, clean and hone, clean and assemble, loosen the bleeder screw C. Loosen the bleeder screw, disassemble, clean and hone, clean and assemble D. Disassemble, clean and hone, loosen the bleeder screw, clean and assemble

Answer 162

The correct answer is C. Before rebuilding a wheel cylinder, first make sure that the bleeder screw can be loosened before disassembling the unit. If the bleeder screw breaks off, the wheel cylinder must be replaced.

Question 163

A vehicle's ABS warning light is on and a DTC for the left front wheel speed sensor is found in the computer's memory. When check with an oscilloscope, the waveform for the left wheel speed sensor is erratic and uneven. Technician A says the sensor air gap is excessive. Technician B says the tone ring is probably damaged. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B

Answer 163

The correct answer is B. A tone ring with chipped or damaged teeth will cause an erratic, uneven waveform. Technician A is wrong because excessive air gap would cause a low amplitude waveform.