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.