ASE A5 Brake Systems Practice Test, Exams of Automobile Engineering

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ASE A5 Brake Systems Practice Test

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-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 returning spring. The purpose is to have both front and rear brakes apply simultaneously. This prevents the front brakes from locking up during light brake applications. The driver of a vehicle with power disc/drum brakes says that the brake pedal moved slowly co 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 ECCS 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. What is the purpose of the master cylinder residual check valve(s) on vehicles equipped with drum brakes? A. Allowed 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 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 replaced with single-flared steel tubing using flare nuts and unions. D. Replace the leaking line with double-flared steel tubing GRRSneeanswennel>. Steel cubing of the same size, type, and length with double flared ends must be used when replacing a traditional SAE double inverted flair style hydraulic brake line. 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 runouc.{HRBISHeenamswenIeC. Tf 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. 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 prebably the cause. Who is right? A, Technician A only B. Technician B only C. Both A and B D. Neither A or B-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, 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? A, Technician A only B. Technician B only C, Both A and B D. Neither A or B-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. 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-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. 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. Technician A says that DOT 5 brake fluid had a lower boiling point than DOT 4. Technician B says that DOT 4 brake fluid is silicene-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-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. 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 IIGESEEEEESED 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. 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-RS@ORSeuanswenIeC. 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 che 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. Technician A says that a caliper seal installed in the caliper bore is called a stroking seal. Technician B says that when che brake pedal is released, the piston in the caliperpves 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. Neher A 0+ 5 EASES 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. When replacing disco brake pads, you must bottom the caliper piston in its bore to create room for the new pads. Which of the following is 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 caliper. The 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 could 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. D. A level becween 10-20% CSSRERIRRED Maximum braking effectiveness is achieved when tire slip is maintained at a level between 10-20%. 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 TCC ERED. 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 Jock and skid during sudden stops because the fluid pressure to the rear wheel cylinders would be unregulated. 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. pusheod ESSERE 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. A customer complains chat the brake warning light comes on whenever the brake pedal is depressed while driving. All of the following could cause the 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. IRR ROHCEANSenIS BD. 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. The MOST common cause for premature front brake pad wear in disc/drum system is: A, Seized calipers B. Faulty master cylinder C., Improperly adjusted rear shoes D, Malfunctioning metering valve-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. 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-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. To determine if an intermittent ABS problem is related to an erratic wheel speed sensor signal, which of the following should be used? 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-The correct answer is > both technicians are right. Both methods are commonly used to adjust tapered roller bearings. Consule the vehicle service manual for the specific adjustment procedure. 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 [CE SEEREEED A seized caliper piston can cause a brake pull or 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. Technician A says that, when testing a proportioning valve, the pressure at the outlets to the rear brakes should rise at a faster rate, once transition pressure is reached. Technician B says that vehicles with diagonally-split 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-The correct answer is B. Vehicles wich 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. All of the following disc brake rotor measurements can be performed using a micrometer EXCEPT: A, Parallelism B. Thickness C, Runout 0. Tp ETRE. lateral runout is measured using a dial indicator. All of the other measurements can be made using a micrometer. When 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 SOHSeUMnSWenIs!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 dise brake pads. 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,-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. 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. Technician A says that ABS wheel speed sensor gap should be adjusted with a non-magnetic feeler gauge. Technician B says chat 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-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 co wear off during vehicle operation. 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 JRRROHSCuanS WEES. Tapered roller bearings are usually used in non-drive axles. All of the other statements are true. All of the following could cause the parking brake to net hold a vehicle on a grade EXCEPT: A. Seized cables B, Excessive rear brake shoe-to-drum clearance C. Seized wheel cylinder D. Broken parking brake linkage HRBISeeeanswenIsC. The parking brake system engages the rear brakes mechanically; a seized wheel cylinder would not affect parking brake operation. 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. spe ws ESTERS . Minimum thickness is checked when inspecting a disc brake rotor, All of the other measurements mentioned should be made when inspecting a brake drum. A vehicle's brake pedal is pumped rapidly 20 times and chen held down. The master cylinder cover is then removed and when the pedal is released, a geyser is seen coming from 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? A, Technician A only B, Technician B only C. Both A and B D. Neither A or B-The correct answer is A, Pumping the brakes compresses the air an d when the pedal is released, the compressed air pushes the hydraulic fluid back through the lines, causing it co 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. Technician A says that RWAL ABS systems must be diagnosed using a scan tool. Technician B says thac the abs arming light will only come on when there is a fault in che system. Who is right? A. Technician A only B. Technician B only C. Both A and B fluid. Technician B says chat 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-ERRROHECEAHOMET 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, A complete front brake service has just been performed on a vehicle with disc brakes: rotora turned, calipers rebuilt, new brake pads, bearings repacked and adjusted. However, when the vehicle is read 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 lining compound chosen C, Over-torqued lug nuts D. Incorrect bleeding seq uence {RSESnectanswenisC. 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. 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 [TCS RSNNE. 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 a dcum brake systems in order to maintain a slight pressure in the brake lines and wheel cylinders, which keep wheel cylinder piston 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 brake pressers, particularly during hard stops. Technician A says that an integral ABS system is an add-on system. Technician B says that a non- integral ABS system is high-pressure system. Who is right? A, Technician A only B. Technician B only C. Both Aand B D. Neither A or B-The correct answer is D, neither technician is right. The non-integral ABS system is added on the vehicle's existing hydraulic brake systen, and is generally a low-pressure arrangement. ‘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. 1.20 SSeS The diameter of brake drums mounted on the same axle must be withing 0.010-in. of one another. Absorption of 3% moisture can reduce the boiling point of DOT 3 brake fluid by what percentage? A. 10% B. 20% C. 25%