ASE Brake A5 practice test
metering valve
A metering valve provides balanced braking by delaying the application of the front brakes, allowing fluid pressure to overcome rear brake spring pressure to engage just before the fronts. Without this valve, the front disc brakes apply almost instantly while the rear brakes still must overcome spring pressure. The vehicle would nosedive. Nosediving is a symptom of a faulty metering valve and may cause vehicle instability and skid.
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?
A only
***IMPORTANT TO KNOW***
A quick take up master cylinder is used along with low drag brake calipers. Low drag brake systems are more fuel-efficient than standard systems because the pads are moved further away from the rotor after application. when the quick take up master cylinder is faulty; the vehicle will have a low brake pedal. The master cylinder is not providing the volume needed to take up the space between the friction material and the brake rotor.
Which of the following conditions can cause brake pedal fade?
a. Seized wheel cylinder piston b. Brake drum machined beyond its limit c. Leakage past the master cylinder cups d. Air in the hydraulic system CORRECT ANSWER IS B
A spongy brake pedal may be caused by:
Air in hydraulic system
A spongy brake pedal on a vehicle with 4-wheel disc brakes with a longer than normal travel indicates which of the following?
Air in the hydraulic system
portioning valve
controls pressure to the rear brakes. used to prevent rear wheel lock up
the front brake rotors and pads are being replaced on a vehicle equipped with a tcs and 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?
B only
A vehicle with 4-wheel disc brakes has a brake squeal. Technician A says a defective proportioning valve could be the cause. Technician B says disc brake squeal is often caused by movement of the disc brake pad during braking. Who is right?
B only To reduce disc brake squeal, all mating surfaces of the brake should be clean and lubricated. Always use OEM recommended clips and anti-squeal shims. To further reduce noise, do not machine a disc brake rotor more than absolutely necessary. Technician A is wrong because the proportioning valve only affects brake lockup and is not used on 4-wheel disc brakes only on disc/drum combinations.
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?
B only 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.
When performing a vacuum booster function test, you should begin by pumping the brake pedal several times _______________.
with the engine off
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
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
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 A and B
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 A and B
A power assist brake booster push rod that is to short will cause which of the following?
Excessive brake pedal travel A short push rod length will have to travel farther for contact and result in excessive pedal travel.
On a car with a drum/disc system, the front brakes lock up on light pedal application. This problem could be caused by a bad:
Metering valve
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?
Neither A nor B Both technicians are wrong because this is how power brakes are supposed to operate.
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?
Neither A nor B 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.
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?
Neither A nor B Both technicians are wrong. The brakes on quick take up systems use the same bleeding procedure as those without this valve.
Brinelling (Definition).
One or more indentations on bearing races usually caused by high static loads or application of force during installation or removal.
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
The component in the Figure is involved what procedure?
Replacing sealed wheel bearing
This question has the word EXCEPT. For this question, look for the choice that could NOT cause the described situation. Read the entire question carefully before choosing your answer. All of these would cause a low brake pedal, EXCEPT:
Seized caliper piston A seized caliper piston could cause the pedal to be high with reduced braking power.
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?
Tech A only 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.
On a car with single piston floating caliper disc brakes, the disc brake pad between the caliper piston and the rotor is badly worn. The other brake pad is slightly worn. Technician A says excessive rotor run out could be the cause. Technician B says insufficient clearance between the pads and caliper slider could be the cause. Who is right?
Tech B only Insufficient clearance between the pads and caliper slider causes the slider not to move and only applies one brake pad causing only that pad to wear. Technician A is wrong because excessive rotor runout will cause brake pulsations with no effect on wear.
A vehicle has a very erratic brake pulling concern while applying the brakes. All of the following items could cause this erratic pull EXCEPT:
a. Excessive tire pressure b. Four-wheel alignment c. Seized caliper piston on the other side d. Steering gear problem CORRECT ANSWER IS A
Brinelling
on a bearing that has been shocked loaded, the race(cup) of the bearing can be dented. what is this type of bearing failure called?
***IMPORTANT TO KNOW***
proportioning valve only affects brake lockup and is not used on 4-wheel disc brakes only on disc/drum combinations.
DOT 5 contains BLANK
silicon based
