ASE A5 Flashcards
What is the most cost efficient method of correcting excessive lateral runout on a disc rotor?
Indexing, it 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.
Which disc brake caliper design allows the brake pads to be removed without removing the caliper?
A fixed caliper, because the pads can be removed while the caliper is mounted in place.
What should be used to clean a disc brake rotor after it is machined?
Soap and water.
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?
Technician A is correct because surge bleeding can be used when manual or pressure bleeding doesn’t work.
Technician B is also correct because, surge bleeding churns the air in the wheel cylinder in order to loosen any pockets of air.
Both technicians are correct.
What should be used to determine if an intermittent ABS problem is related to an erratic wheel speed sensor signal?
Digital storage oscilloscope because it samples the electrical signal over 250,000 times per second.
When replacing disc brake pads, you must bottom the caliper piston in its bore to create room for the new pads. What is the proper procedure?
- Connect a hose to the caliper bleeder screw.
- Insert the other end of the hose into a container.
- Open the bleeder screw.
- Use a C-clamp to slowly bottom the piston.
Fine filing can be used to apply a non-directional finish to a disc brake rotor. True or False?
False, files are not used to apply a non-directional finish on a disc brake rotor.
A customer says that he has just replaced his front disc brake pads himself and now the ABS warning light is on. What could be the cause?
Damaged/incorrect wheel speed sensor and stuck ABS solenoid valves.
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. Over torqued lug nuts are the cause of the problem. True or False?
True, over tightening the lug nuts can distort the rotor and create excessive run out.
What is the correct wheel cylinder repair process?
Loosen the bleeder screw, disassemble, clean and hone, and clean and assemble
Vacuum should exist on the booster side but not on the engine side. True and False
True
When rough machining a brake drum, the depth of cut and spindle feed rate should be?
0.010-0.015-in at high feed rate.
Tech A says that DTCs can be accessed from any ABS system using flash diagnostics. Tech B says that ABS system tests can be performed with a bi-directional scan tool. Who is right?
Technician B is correct because a bi-directional scan tool can be used to perform tests on ABS system components.
Technician A is wrong, only a few ABS systems are compatible with flash diagnostics.
Tech A says that DOT 5 brake fluid has a lower boiling point than DOT 4. Tech B says that DOT 4 brake fluid is silicone based and should never be used in an ABS system. Who is right?
Both techs are wrong because DOT 4 has a lower boiling point than DOT 5, and DOT 5 is silicone based and should not be used in any ABS system.
A seized caliper piston could cause a pulsation to be felt in the brake pedal. True or False?
False because a seized caliper piston can cause a brake pull or a hard pedal, but it would not cause a pedal pulsation.
A driver complains that the 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 concludes that:
The system is operating normally and the wheels are traveling at different speeds because on a cobblestone road the signals coming from the wheel speed sensors are not in sync with each other, the ABS system sees this as wheel lockup and responds by engaging the system.
The purpose of an anti-lock brake system is to maintain tire (wheel) slip at what level?
Between 10-20% level to achieve maximum braking effectiveness.
Absorption of 3% moisture can reduce the boiling point of DOT 3 brake fluid by what percentage?
25%
After applying the brake pedal several times to deplete the fluid reserve in the accumulator of 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?
The pedal should initially move downward before rising up.
Runout measurements can be performed using a micrometer. True or False?
False because runout is measured using a dial indicator.
Parallelism, thickness and taper can be measured with a micrometer.
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 valve in the hydraulic system switched on the light?
The pressure differential valve.
What kind of problem would be caused by using a residual check valve in a disc brake master cylinder?
Increased brake pad wear because it would cause the pistons to keep the pads applied even when the pedal is released.
Tech A says that a caliper seal installed in the caliper bore is called a stroking seal. Tech 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?
Technician B is correct because the outward movement of the piston during braking causes the piston seal to distort. Once the brakes are released, the seal returns to its original shape forcing the piston to move back in its bore.
Technician A is wrong because a caliper seal installed on the PISTON is called a stroking seal.
Tech A says that all 3-channel ABS systems use only 3 wheel speed sensors. Tech 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?
Technician B is correct because a channel is an independently controlled fluid path from the hydraulic modulator to the wheel.
Technician A is wrong because a 3-channel system can have a speed sensor at each car wheel, even though there are only 3 individually controlled hydraulic circuits, two in the front and one in the rear.
Two technicians are discussing traction control systems. Technician A says that some traction control strategies do not use the brakes to control wheel spin. Technician B says that a fault in the ABS does not affect traction control. Who is right?
Technician A is correct, some manufacturers reduce power to the spinning wheels by retarding ignition timing, cutting off fuel injection to certain cylinders and mechanically closing the throttle.
Technician B is wrong, because the traction control uses the same components as the ABS.
Tapered wheel bearings are most commonly used on drive axles. True Or False?
False, tapered wheel bearings are used on NON-drive axles.
Tech A says that when rebuilding a caliper with a stroking seal, the condition of the caliper bore surface is critical. Tech 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?
Both technicians are correct because the caliper bore must be smooth to prevent leaks, and a fixed seal needs a surface in good condition to provide a good seal.
What is the purpose of the master cylinder residual check valve on vehicles equipped with drum brakes?
It prevents air from entering the hydraulic system by using low pressure to keep the lips of the piston cups tight against the cylinder walls.
When replacing an integral hub/bearing assembly on a fwd car, the steering knuckle must be removed. True or False?
False.
On a vehicle with single-piston floating caliper front disc brakes, the brake 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. Which technician is right?
Technician B is correct because a frozen caliper piston will keep its pads applied even when the pedal is released, this will also cause a front end pull.
Technician A is wrong because rotor runout will only cause a pulsating brake pedal.
Grease on the linings can cause disc brake squeal. True or False?
False, grease on the linings can cause the vehicle to pull when brakes are applied, but would not cause squeal.
Excessive slack in the parking brake cables can be eliminated on most vehicles by making an adjustment at the what?
Equalizer because by tightening its adjusting nut it is used to shorten one or more of the parking brake cables to remove slack.
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?
The brake caliper, because the heat generated while stopping breaks down the corrision inhibitors in the brake fluid.
During a brake inspection, an area of the vacuum brake booster below the master cylinder is found to be damp. Tech A says that this is normal. Tech B says that any evidence of fluid indicates a leak and the master cylinder must be replaced. Who is right?
Technician A is correct because a small amount of fluid present is normal due to the lubricating action of the master cylinder bore end seal.
Two technicians are discussing brake bleeding procedures. Technician A says gravity bleeding is a relatively quick way to bleed a brake system. Technician B says silicone brake fluid cannot be gravity bled. Who is right?
Both technicians are wrong.
Technician A is wrong because gravity bleeding is the easiest but more time consuming method of brake bleeding.
Technician B is wrong because gravity bleeding does not agitate the fluid and generate air bubbles, which is an advantage for systems with DOT 5 silicone fluid.
A blocked master cylinder compensating port can cause a vehicle to pull to one side when the brakes are applied. True or False?
False, a blocked master cylinder port could cause all brakes to drag but would not cause a brake pull.
Bench bleeding is a procedure for removing air from a hydraulic system. True or False?
False, bench bleeding is a procedure for removing air from the master cylinder only.
Leading-trailing type drum brakes are self energizing.
True or False?
False, because the fixed anchor on the backing plate prevents the shoes from transferring their force to one another.
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, what is the proper course of action?
Replace both rotors, because composite and cast rotors should not be mixed on the same axle.
Minimum thickness should be used to determine the serviceability of a drum brake. True or False?
False, minimum thickness is checked only when inspecting a disc brake rotor.
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. What is the problem?
The metering valve release button is not activated, because 25psi is too low to open the metering valve so you must manually open it by pushing the button. 75 - 125 psi is the required minimum pressure to open.
The MOST common cause for premature front brake pad wear in a disc/drum system is?
Improperly adjusted rear shoes.
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?
Technician B is correct.
Technician A is wrong because minor surface imperfections are OK as long as they do not enter the dust boot groove area.
While on a road test, a technician notices that the rear wheels lockup and the car skids when attempting to stop quickly from a high speed. The most likely cause of this problem is a defective?
A defective proportioning valve, because it can cause the rear wheels to lock and skid because the fluid pressure to the rear wheel cylinder would be unregulated.
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 spout is seen coming form the reservoir. Tech A says that this indicates that air is trapped in the system. Tech 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?
Technician A is correct because when there is air in the system pumping the brakes compresses it and when the pedal is released, the compressed ait pushes the hydraulic fluid back through the lines, causing a spout.
Technician B is wrong because a small spout should appear over the reservoir, only when the pedal is applied, not released.
A frozen star wheel can cause drum brake drag. True or False?
False, a frozen star wheel would prevent the automatic adjuster mechanism from working which would cause lining wear.
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?
Technician A is wrong, use only fresh clean brake fluid to lubricate the honing stones.
Technician B is also wrong, if the piston can be inserted with a 0.003-inch feeler shim in place, the cylinder is oversize and cannot be rebuilt.
Both technicians are wrong.
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?
Technician A is wrong because only non-integral systems are considered add-on’s.
Technician B is wrong because non integral ABS systems are low-pressure.
Both technicians are wrong.
What tool should be used to measure the thickness of a scored rotor?
An outside micrometer with pointed anvil and spindle because its pointed tips fit into the grooves of scored rotors, accurately measure the thickness.
With foot pressure applied, the brake pedal on a vehicle with vacuum assisted power brakes moves down slightly when the engine is started. Tech A says that this condition can be caused by a leaking power brake booster diaphragm. Tech B says that the cause could be a faulty power brake booster check valve. Who is right?
Both technicians are wrong because if the pedal moves down slightly on a vehicle with vacuum assisted power brakes, everything is operating correctly.
Two techs are discussing the duo-servo type drum brake design. Tech A says the brake lining on the secondary shoe is usually longer and thicker than the brake lining on the primary shoe. Tech B says the primary shoe is installed toward the rear of the vehicle. Who is right?
Technician A is correct because the friction developed by the secondary lining is greater than the primary lining. So the secondary shoe is typically longer and thicker than the primary shoe. Technician B is wrong because the primary shoe is installed facing the direction of forward motion.
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. Tech A says that this is normal. Tech B says that the booster check valve is leaking. Who is right?
Technician B is correct because the lack of power assist indicates that the check valve is leaking.
Technician A is wrong because there should be at least one power assist before the pedal gets hard to push.
Brakes that drag or fail to release can be caused by which of the following conditions in the master cylinder?
A clogged compensating port, because if it’s clogged it will create a pressure build up, which is what causes the brakes to drag or fail to release.
A leaking check valve can cause a problem in the Hydro-Boost system. True or False?
False, a check valve is used on a vacuum power booster, hydro boost system uses power steering pump fluid.
Which component in the Hydro-Boost system provides power assist if there is a loss of hydraulic pressure to the system?
The accumulator, it can supply enough power assist for two stops if there is a loss of hydraulic pressure.
What 3 brake symptoms can be caused by wheel bearing problems?
Pedal pulsation, brake pull and grabbing.
Technician A says the rear brake shoes should be properly adjusted before adjusting the parking brake. Tech B says the parking brake lever should be disengaged before adjusting the equalizer. Who is right?
Technician A is correct because the brake shoes must be correctly adjusted for the parking brake to work properly.
Technician B is wrong because the parking brake lever must be engaged a number of clicks before adjusting the equalizer.
A seized wheel cylinder could cause a parking brake to not hold a vehicle on a grade. True or False
False, the parking brake system engages the rear brakes mechanically; a seized wheel cylinder would not affect parking brake operation.
The hydraulic system on a vehicle with integral ABS is to bled. Tech A says that the front brakes can be bled in a conventional manner. Tech B says that both front and rear brakes can only be bled using the pressure from a fully charged accumulator. Who is right?
Technician A is correct since it is the booster piston that supplies fluid to the front brakes.
Technician B is wrong because only the rear circuit needs a fully charged accumulator.
Two technicians are discussing Electronic Stability Control (ESC) systems. Technician A says the ESC 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 ESC control module uses inputs from the lateral acceleration and yaw rate sensors to calculate the vehicle’s actual path. Who is right?
Both technicians are correct.
Technician A says as brake fluid ages, it can corrode ABS control valves. Technician B says brake fluid corrodes the copper in the brake lines. Who is right?
Technician B is correct.
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
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?
Technician B is correct.
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.
A leak in the brake hydraulic system could cause a hard brake pedal on a vehicle with power brakes. True or False
False because a leak would cause a soft pedal. A frozen caliper would prevent retraction of the piston resulting in a hard pedal.
Tech A says that ABS wheel speed sensor gap should be adjusted with a non magnetic feeler gauge. Tech 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?
Technician A is correct.
Technican B is incorrect because it is not necessary to remove the paper spacer, it is designed to wear off during vehicle operation.
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?
Technician B is correct, a tone ring with chipped or damaged teeth will cause an erratic, uneven waveform.
Technician A is wrong, excessive air gap would cause a low amplitude wave-form.
A customer complains that the brake warning light comes on whenever the brake pedal is depressed while driving. A short to ground in the warning light circuit is the issue. True or False?
False because a short to ground would cause the light to stay on all the time even without the pedal being pressed.
A leak would cause the light to come on when the pedal is pressed because it causes unequal pressure to be applied to one side of the pressure differential piston.
A customer complains that their vehicle pulls to the right when the brakes are applied. Tech A says a restricted brake line to the left caliper can cause this problem. Tech B says a malfunctioning proportioning valve is probably the cause. Who is right?
Technician A is correct because a restriction will cause a drop in fluid pressure to the affected caliper which will cause the caliper to not have as much force as the other side, so the car will pull to the side where the brake force is greatest which would be the right side.
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?
Both technicians are correct.
Tech 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. Tech B says that vehicles with diagonally hydraulic systems must have the proportioning valve tested twice. Who is right?
Technician B is correct because vehicles with diagonally-split hydraulic systems have dual proportioning valves, so if a problem is suspected, both valves must be tested.
Technician A is wrong because when testing a proportioning valve, the pressure at the outlet to the rear brakes will rise at a slower rate not faster.
The diameter of drums mounted on the same axle should be measured within how many thousands of an inch of one another?
0.010-in.
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?
Metering valve because it delays the flow of brake fluid to the front calipers.
Tech A says that when a rotor is machined, an equal amount of material must always be removed from both sides. Tech B says that the minimum thickness dimension cast into the rotor is the dimension that the rotor can be machined to. Who is right?
Both Techs are wrong because the minimum thickness dimension is usually the ‘discard dimension’ and when you’re machining a rotor you do not have to remove an equal amount of material from both sides unless the vehicle has fixed calipers.
A vehicle exhibits intermittent ABS activation, but when the technician connects a scan tool to the DLC, no DTCs are found. What 3 things could be the cause?
Damaged tone wheel teeth, loose wheel bearing, and rust under the wheel speed sensor mount.
Tech A says that rear wheel ABS systems must be diagnosed using a scan tool. Tech B says that the ABS warning light will only come on when there is a fault in the system. Who is right?
Technician A is wrong because rear wheel abs systems use flash-code diagnostics.
Technician B is wrong because the abs light will come on whenever the key is turned ON and will go off if there are no faults in the system.
Both Technicians are wrong
Seized cables have caused the parking brake pedal on a vehicle with automatic parking brake release to remain depressed when the vehicle is placed in drive. True or False?
False
Hard spots are cause for brake rotor resurfacing. True and False?
False, resurfacing does not remove hard spots.
Tech A says that tapered roller bearings can be adjusted using a torque wrench. Tech B says that tapered roller bearings are adjusted using a dial indicator. Who is right?
Both techs are correct because both methods are used to adjust tapered bearings.
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. Tech A says that this means the fluid should be topped off with DOT 4, which has a higher boiling point than regular brake fluid. Tech 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?
Neither tech is correct because purple is the color of silicone fluid, and only DOT 5 fluid should be used to top off the reservoir.
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?
Both technicians are correct.
The brake pedal is low and spongy; all brake adjustments have been completed according to specifications. The cause of the problem could be
A weak hydraulic hose.
A vehicle has no brake pedal free play. This problem may cause
pressure build-up and dragging brakes.
There are signs of paint removal and peeling on the power brake booster right below the master cylinder. The cause of this could be
A leaking secondary cup on the primary piston.
When removing the master cylinder, you must drain it first. True or False?
False
Brake systems contain double wall copper tubing, high pressure rubber tubing, double wall steel tubing, and flare nuts. True or False?
False, brake systems do not contain double wall copper tubing, copper corrodes easily and can expand due to high pressures
A metering valve delays pressure to which set of brakes under which braking condition?
The front brakes under light braking.
To test the brake warning light circuit you must
Ground the warning switch wire with the ignition on.
During a surge bleeding procedure you must…
Pump the pedal quickly several times with the bleeder screw closed.
A vehicle experiences brake squeal during brake application. Technician A says the drums may be distorted. Technician B says the backing plates may be bent. Who is right?
Both technicians are right.
Brake squeal may be caused by bent backing plates, distorted drums
If the drum diameter is less than specified, replace the drum. True or False?
False, it is fine as long as the shoes fit inside the diameter
While discussing brake backing plates, Technician A says a bent backing plate may cause brake grabbing. Technician B says a loose anchor bolt may cause brake chatter. Who is right?
Technician B is correct.
While servicing a wheel cylinder you must?
The piston cups should be lubricated with clean brake fluid before installation.
What must be done while assembling the brake shoes and related hardware?
The adjuster must be installed in the proper direction.
What will NOT cause a car to pull to one side while braking?
Seized master cylinder piston.
On a single piston floating caliper, the inside brake pad lining is worn out, but there is very little wear on the outside pad lining. The cause of the problem could be
Worn caliper pins and bushings.
On a vehicle with front disc and rear drum brakes, a scraping noise is present in one front wheel while braking. The cause of this problem could be
The pad wear sensor contacting the rotor.
After honing a brake caliper, the maximum allowable increase in caliper bore diameter is?
0.001 in.
What must be done while reassembling a brake caliper?
Coat the piston seal and boot with clean brake fluid
When adjusting the parking brakes on a vehicle equipped with rear disc brakes
The parking brake cable should be adjusted with the parking brake on one click so there will be a slight drag in the wheels.
There is evidence of brake fluid leakage into the engine. The cause of the problem could be.
A defective one-way check valve in the booster vacuum hose.
An open wheel speed sensor winding may cause red brake warning light to illuminate. True or False?
False
A master cylinder reservoir cap’s rubber gasket is deformed. What would cause in this condition?
Brake fluid contamination.
Two technicians are discussing ABS hydraulic modulators. Technician A says the inlet valve is a normally closed valve. Technician B says the outlet valve is a normally open valve. Who is correct?
Both technicians are wrong.
The inlet valve is a normally open valve. The outlet valve is normally closed.
What is NOT a part of an integral ABS unit?
Vacuum booster
A vehicle stops but the brake pedal fades completely to the floorboard afterwards. There are no external leaks. What is most likely the cause?
Master cylinder cup seals wear and create an internal leak.
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?
Both technicians are correct
Rust and corrosion have damaged the brake lines on the axle of a light truck and caused them to leak fluid. These brake lines cannot be repaired and must be replaced. Technician A says double flare copper tubing is used for brake lines. Technician B says single flare steel tubing is used for brake lines. Who is correct?
Technician A is wrong because copper tubing is not used for brake lines.
Technician B is wrong because double flare steel tubing is used for brake lines.
Neither technician is correct.
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?
Both techs are correct.
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?
Technician B is correct
An integral drum parking brake system is being discussed. Technician A says a binding cable will prevent parking brake application. Technician B says this system contains a brake strut. Who is correct?
Both technicians are correct.
The ABS warning light is illuminated on a vehicle. The LF wheel speed sensor’s tip and tone ring are damaged. Technician A says to check the wheel bearing for looseness. Technician B says an insufficient gap may have caused this damage. Who is correct?
Both technicians are correct.
Technician A says accumulators are found only on non-integral ABS systems. Technician B says some integral ABS units contain high pressure accumulators that must be discharged before repair. Who is correct?
Tech A is wrong. Accumulators are found on integral and non-integral ABS systems.
Tech B is correct. High pressure units can be dangerous and must be discharged before removal.
Technician A says ABS control units are programmed to ignore speed sensor input variations below a certain threshold.
Technician B says a one-channel ABS system controls hydraulic pressure to the rear brake units. Who is correct?
Both technicians are correct.
During a brake inspection one rotor is found to be much hotter than the other. Technician A says this could be caused by a sticking brake caliper. Technician B says this could be caused by the brake caliper piston seal. Who is correct?
Both technicians are correct.
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?
Tech A is wrong. A residual check valve is used on vehicle’s with drum brakes.
Tech B is correct. A residual check valve provides constant low pressure.
It is noticed during a brake inspection of a front disc rear drum brake system that one shoe is worn more than the other. Technician A says that this is caused by a faulty residual check valve. Technician B says this is caused by a faulty proportioning valve. Who is correct?
Both technician are wrong.
A vehicle with ABS brakes has an audible clicking noise when it is first started. The noise goes away after a few seconds. Technician A says this is one of the hydraulic valves in the hydraulic valve assembly sticking. Technician B says this is a normal condition. Who is correct?
Technician B is correct.
A vehicle with a vacuum brake booster has a hard pedal with little stopping power. Technician A says a kink in the check valve’s hose will result in this condition. Technician B says a vacuum booster needs at least 12 Hg of vacuum to operate properly. Who is correct?
Tech A is correct. An bad brake booster, check valve or a kink in a hose will result in a hard brake pedal.
Tech B is wrong, A brake booster needs more vacuum, between 17-21 Hg to function properly.
Technician A says passive permanent magnet ABS wheel speed sensors produce an A/C voltage signal. Technician B says input from wheel speed sensors are used for anti-lock brake, electronic traction control, and electronic stability control systems. Who is correct?
Both technicians are correct.
Tech A is correct, the signal is sent to the electronic controller for anti-skid, stability, and traction control.
Tech B is correct ,the signal is sent to the electronic controller for (ABS) anti-lock brake, (TCS) traction control system, and (ESC) electronic stability control.
The brakes of a four wheel disc brake system are self-applying and locking up after only a few miles of travel. Which of the following is the MOST likely cause of this condition?
A blocked master cylinder vent port, if the port is blocked, excessive pressure will cause the brake units to self-apply.
A front wheel drive vehicle with four wheel disc brakes is pulling to the left. Technician A says an external kink or internal restriction in the LF brake line will result in this condition. Technician B says to use a compression fitting to repair a section of brake line. Who is correct?
Tech A is correct, The brake caliper is unable to create enough pressure to bypass the kink and return the fluid to the master cylinder. This keeps the brake applied at that wheel resulting in brake drag.
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 the pad wear sensor contacting the brake rotor. Who is correct?
Technician B is correct
A vehicle’s right front wheel has a growl that increases with vehicle speed. The MOST likely cause is?
A worn wheel bearing will cause a growl that increases with vehicle speed.
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?
Both technicians are correct.
Tech A is correct, this type of master cylinder is used with low drag brake calipers.
Tech B is correct, the quick take up master cylinder provides more brake fluid volume to take up the additional space between the pads and the rotor.
During a test drive an excessive vibration is felt in the steering wheel only when the brakes are applied. The front brake rotors have just been replaced for this same problem. Which of the following is MOST likely to result in this vibration.
Rusty hub flange
A vehicle has a hard brake pedal at all times. Which of the following would cause this condition?
A faulty vacuum booster will result in a hard brake pedal.
A vehicle has a growling sound that changes in pitch as the vehicle is lightly swerved from left to right. The noise is loudest during left hand turns. What is MOST likely to result in this condition?
Faulty right front wheel bearing, the bearing on the outside wheel of the turn is loudest.
Technician A says an outside micrometer is the preferred tool for measuring rotor lateral runout. Technician B says a dial indicator is the preferred tool used for measuring rotor thickness. Who is correct?
Both technicians are wrong, A micrometer is used for measuring rotor thickness. A dial indicator is used to measure lateral runout.
What 3 input sensors are used as inputs for (TCS) traction control systems?
Yaw rate sensor, Steering angle sensor, and wheel speed sensor.
A technician is lubricating rubber brake components while performing a brake job. Technician A says to use a high temperature silicon based lubricant. Technician B says to use a good petroleum based lubricant. Who is correct?
Technician A is correct.
Technician B is wrong, Petroleum based products should never be used in brake applications.
The red brake warning light on the instrument panel illuminates only when the brakes are applied. What causes this?
Air in the hydraulic system.
ISO flare nuts can be used interchangeably with double flare nuts. True or False
False, ISO flare nuts cannot be mixed with double flare nuts. Doing so can cause leaks.
What would cause the brake pedal to slowly move downward during a brake application?
Brake fluid leaking past the master cylinder cups
Fill in the blanks:
Silicon-based brake fluids have a _____ shelf life and ____ absorb water.
long; will not
Fill in the blanks:
The _____ end should be replaced each time a brake hose is removed. When a brake hose is installed, always install and tighten the _____ end first.
male; male
When a front caliper is seized, the vehicle will pull to the opposite side of that caliper. True or False?
True
Fill in the blanks:
Normal brake pedal free play is usually _____ to _____ of an inch
1/16; 1/4
A hard brake pedal may be caused by?
Contaminated brake fluid
If no turbulence is seen in the reservoirs as the brakes are being applied, what should be done to correct it?
The bolts for the vacuum booster may need to be loosened, the brake pedal pushrod length may need adjusted, or the master cylinder may need to replaced.
When removing the master cylinder, Technician A thinks that the pushrod must be disconnected from manual braking systems first. Technician B thinks the pushrod must be connected first, but for power braking systems. Which is correct?
Technician A is correct
What would cause requiring excessive pedal effort?
Swollen master cylinder cups
If there is evidence of small fluid leakage on the brake booster, it is most likely caused by ?
leaking from the secondary cup on the primary piston.
A customer has a complaint of a hard brake pedal. Technician A believes it is either caused by contaminated brake fluid or a plugged quick take-up valve. Technician B thinks its caused by weak break hoses. Which is correct?
Neither technician is correct.
Swollen master cylinder cups, glazed brake linings, or a defective brake booster cause a hard brake pedal.
Flare nuts do not rust or corrode. True or False?
True
If there is slight dampness in the area surrounding the master cylinder, this is most likely caused by?
Nothing, this is normal.
Fill in the blanks:
_____ absorbs less moisture and has a higher boiling point than _____.
DOT 4; DOT 3;
What could keep the brake pedal partially depressed, resulting in brake drag?
An improperly adjusted cruise control switch
DOT 5 silicone brake fluid should be used in antilock braking systems. True or False?
False.
What could cause brake dragging on only one front caliper?
The quick take-up valve may not be allowing fluid movement from the reservoir into the primary piston area.
Brake drag and pull to one side of the vehicle may be caused by?
Dented brake lines.
If brake dragging occurs only on one front caliper, the quick take-up valve may not be allowing fluid movement from the reservoir into the primary piston area. True or False?
True
Excessive pedal effort may be caused by?
swollen master cylinder cups and a corroded master cylinder.
Brake fluid leaking past the master cylinder cups may cause the brake pedal to?
Move slow and downward during a brake application.
An improperly adjusted stoplight and cruise control switch may keep the brake pedal partially depressed, but will not result in brake drag. True or False?
False
While discussing poor stopping, dragging, high or low pedal, or hard pedal, Technician A says that glazed brake linings increase pedal effort. Technician B says that a defective brake booster decreases pedal effort. Who is right?
Technician A is correct.
A binding pedal linkage may cause improper pedal return, and cause brake drag. True or False?
True
While discussing poor stopping, dragging, high or low pedal, or hard pedal, Technician A says that a step-bore master cylinder can be identified by the bulge or larger step diameter in the outside of the master cylinder casting. Technician B says that the step-bore master cylinder uses a larger size bore for the rear of the primary piston than the front of the primary piston. Who is right?
Both technicians are correct
The specified brake pedal free play is usually?
1/16 to ¼ inch
During factory assembly, the pushrod is matched to the booster. It is normally adjusted only when the vacuum booster unit or the master cylinder is serviced. True or False?
True
The brakes are being bled on an older vehicle equipped with a quick take up valve in the master cylinder. Technician A says the quick take up valve must be depressed. Technician B says the brakes on this vehicle cannot be bled. Who is right?
Both technicians are wrong.
The brakes on quick take up systems use the same bleeding procedure as those without this valve.
A power assist brake booster push rod that is to short will cause what?
Excessive brake pedal travel, A short push rod length will have to travel farther for contact and result in excessive pedal travel.
A vehicle with disc/drum brakes requires excessive brake pedal effort to stop. The brake pedal is firm when applied. While starting the engine with the brakes applied, the pedal does not go down slightly. Technician A says excessive brake pedal freeplay could be the cause. Technician B says air trapped in the hydraulic system could be the cause. Who is right?
Both technicians are wrong because the problem is in the power booster. Excessive freeplay delays application and air in the hydraulic system will cause a spongy pedal.
What condition can cause brake pedal fade?
Brake drum machined beyond its limit.
The rear brake linings are soaked with axle grease but still have a lot of lining left on them. Which is the correct way to service these brakes?
Repair leak and replace brake linings.
A vehicle comes in with a complaint of excessive pedal travel before the brakes apply. Technician A says the master cylinder pushrod adjustment is incorrect. Technician B says the cause is a faulty residual pressure check valve admitting air. Who is right?
Technician A is right because if the master cylinder pushrod is too short that will be a delay in application.
Technician B is wrong because a faulty residual check valve if used will cause a spongy pedal due to the ingress of air.
With the brakes applied on a vehicle with power brakes, the pedal moves down slightly when the engine is started. Technician A says the cause could be a leaking power brake booster diaphragm. Technician B says the cause could be a stuck closed residual check valve in the hose from the intake manifold to the power brake booster. Who is right?
Both technicians are wrong because this is how power brakes are supposed to operate.
Technician A says the vacuum supply test involves inspecting the vacuum supply hose for kinks. Technician B says the test involves checking the level of vacuum supplied by the engine or vacuum pump. Who is right?
Both technicians are correct
On a bearing that has been shock loaded, the race (cup) of the bearing can be dented. What is this type of bearing failure called?
Brinelling, it is defined as indentations in the race caused by impact loads or vibrations.
Technician A says a defective wheel or axle bearing can make a growling or rumbling noise. Technician B says a defective wheel displays looseness or excessive play in the steering wheel especially while driving over rough road surfaces. Who is right?
Both technicians are correct.
The front wheel bearings are being adjusted. Technician A says you torque the adjusting nut to a specified torque and back off the nut till it lines up with the hole and install the cotter pin. Technician B says backing off the castle nut will cause the bearing to overheat. Who is right?
Technician A is correct, You torque an adjusting nut to a specified torque and back off the nut till it lines up with the hole and install the cotter pin.
Technician B is wrong because backing off the castle nut will not cause the bearing to overheat.
The ABS (antilock brake system) and TRACTION OFF indicator lights remain ON with the engine running. Technician A says to check for ABS or TCS (traction control system) diagnostic trouble codes. Technician B says you can check for ABS or TCS blink codes by connecting two pins of the DLC (Data Link Connector). Who is right?
Both technicians are correct.
A wheel speed sensor is being diagnosed using the OEM (original equipment manufacturer) diagnostic scan tool. Technician A says to verify wheel speed sensor operation, compare all four wheel speed sensor outputs to vehicle speed on the data list. Technician B says the wheel’s direction of rotation can be verified by looking at the wheel direction on the scan tool data list. Who is right?
Both technicians are correct.
The front brake rotors and pads are being replaced on a vehicle equipped with a TCS (traction control system) and electronic stability control system (ESC). Technician A says the yaw rate and deceleration sensor should be recalibrated. Technician B says the new rotors should be indexed to the hub using a dial indicator for the least amount of runout. Who is right?
Tech B is correct, This is the standard process by many OEMS when a new rotor is installed.
Technician A is wrong because recalibration is not required for these sensors.
The ABS (antilock brake system) amber light does not go off after the engine is started. Technician A says a parking brake not fully released could be the cause. Technician B says when this happens the brakes will operate like a normal non-ABS brake system. Who is right?
Tech B is correct If the amber light is on it indicates an ABS fault and the system will revert to regular brake operation without ABS.
Technician A is wrong because the parking brake only affects the RED Brake Light not the amber.
