ASE A5 Solved Questions And Verified Answers

1. 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 safety switch C. metering valve D. residual check valve 1. 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. 2. 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 2. 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. 3. Which of the following would MOST LIKELY happen if the measurements taken from the check shown above varied from the manufacturer's specifications? A. noisy brake operation B. brake grab or pull C. pulsating brake pedal D. low brake pedal 3. The correct answer is C. Poor rotor parallelism (thickness variation) will cause a pulsating brake pedal. This is due to the caliper piston movement that occurs as the pad rides over the alternating high and low areas on the disc. This action forces brake fluid to flow back and forth from the caliper to the master cylinder, creating the pulsating pedal feedback. 4. 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 4. 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 (5-20 psi) 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). 5. 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 5. 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. 6. 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. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B 6. 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. 7. What is the purpose of the bar that is being removed from the brake assembly shown below? A. to equalize the braking force between the shoes during normal braking B. to center the shoes after each brake application C. to force the shoes into the drum when the parking brakes are applied D. to reduce the distance between the shoes and the drum 7. The correct answer is C. The parking brake strut bar forces the brake shoes into the drum when the parking brake is applied. 8. 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. 8. 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. 9. The set-up shown above is used to check: (dial indicator on rotor face) A. rotor parallelism B. wheel bearing adjustment C. rotor lateral runout D. rotor face wear 9. The correct answer is C. Lateral runout is the movement of the rotor from side to side as it rotates on the steering knuckle spindle. The dial-indicator set-up shown in the illustration is used to make this measurement once the wheel bearing nut has been tightened (bearing play removed). 10. 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 10. 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. 11. 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 says 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 11. 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. 12. 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 12. 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. 13. Technician A says that the tool shown above is used to adjust the brake shoes. Technician B says that the tool shown above is used to determine the inside diameter of the drum. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B 13. The correct answer is A. The illustration shows a technician setting a brake shoe adjustment gauge, or caliper, to the inside diameter of a brake drum. The other side of the gauge is then positioned over the brake shoes and the star wheel turned until the shoes lightly contact each end of the gauge. Technician B is wrong because a brake drum micrometer is used to measure the inside diameter of a brake drum. 14. 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 14. 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. 15. 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 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 15. 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. 16. 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 16. 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. 17. 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. 17. 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. 18. 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 18. 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. 19. 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 19. 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 pushrod is improperly adjusted. 20. 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 20. 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 linings 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. 21. 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 21. 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. 22. 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. 22. 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. 23. 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 23. The correct answer is B. The number of wheel speed sensors used on an ABS system does not necessarily indicate the number of 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. 24. 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 24. 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 from both sides. 25. 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% 25. The correct answer is D. Maximum braking effectiveness is achieved when tire slip is maintained at a level between 10-20%. 26. 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. residual pressure check valve B. pressure differential valve C. metering valve D. proportioning valve 26. 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. 27. 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 27. 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. 28. 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 28. 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. 29. 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 29. 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. 30. 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 bi-directional scan tool. Who is right? A. Technician A only B. Technician B only C. Both A and B D. Neither A or B 30. The correct answer is B. Only a few ABS systems (primarily 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. 31. 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 31. 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. 32. 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 a 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 32. 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. 33. The above measurement is made when replacing all of the following components EXCEPT: A. master cylinder B. vacuum power booster C. brake caliper D. master cylinder pushrod 33. The correct answer is C. Replacing a disc brake caliper would not require measuring master cylinder pushrod length. Measuring pushrod length may be required when replacing any of the other components. 34. 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 34. 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 pushrod. If a large amount of fluid is present, unbolt the master cylinder from the booster and look for signs of leakage. 35. Technician A says that tapered roller bearings 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 35. 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. 36. 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 36. 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. 37. 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 diagonallysplit 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 37. The correct answer is B. Vehicles with diagonallysplit 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. 38. All of the following disc brake rotor measurements can be performed using a micrometer EXCEPT: A. parallelism B. thickness C. runout D. taper 38. The correct answer is C. Lateral runout is measured using a dial indicator. All of the other measurements can be made using a micrometer. 39. 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 39. The correct answer is A. The disc brake pads can usually be removed from fixed calipers while the caliper is mounted in place. Floating and sliding calipers require that the caliper be removed or pivoted out of the way to access the disc brake pads. 40. 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? A. The pedal should initially rise before moving downward. B. The pedal should initially move downward before rising up. C. The pedal should move downward. D. The pedal should rise. 40. 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.