Brakes - part 3

Which of the following conditions can cause brake pedal fade (when the pedal is firm at first, but gradually sinks to the floor with the same pressure applied)

• Seized wheel cylinder piston

• Brake drum machined beyond limit

• Leakage past the master cylinder cups

• Air in the hydraulic system

A vehicle with disc/drum brakes has a hard to push brake pedal. When starting the engine with the pedal applied, the pedal does not drop at all.

Technician A says excessive brake pedal free play could be the cause

Technician B says air trapped in the hydraulic system is the likely cause

Who do you agree with?

• Technician A

• Technician B

• Neither

• Both

A 1999 Ford F150 with drum brakes had a leaking axle seal. You are making an estimate to repair it. You see the seal is leaking, and the drum brake shoes are covered in oil. What do you recommend?

• Replace the axle seal and replace the oil soaked brake shoes

• Replace the axle seal, and clean the oil off the brake shoes

• Replace the axle assembly

• Flush the brake fluid and bleed the brake system

On a car with disc/drum brakes, the front brakes lock up with light pedal application. You should suspect an issue with the:

• Residual check valve

• Proportioning valve

• Pressure differential switch

• Metering valve

All of these EXCEPT one can cause a low brake pedal:

• Brake adjustment

• Loose wheel bearing

• Low brake fluid

• Seized caliper piston

A spongy brake pedal on a vehicle with 4 wheel disc brakes with longer than normal travel indicates which of the following?

• Air in the hydraulic system

• Caliper piston seized

• Parking brake out of adjustment

• Faulty power booster

A car with 4 wheel disc brakes has a brake squeal

Technician A says a defective proportioning valve is a likely cause

Technician B says that squeals are often caused by movement of the brake pad during braking

Who do you agree with?

• Technician A

• Technician B

• Both

• Neither

A vehicle has excessive pedal travel before the brakes apply

Technician A says the master cylinder pushrod is adjusted incorrectly

Technician B says the cause is a faulty residual pressure check valve admitting air

Who do you agree with?

• Technician A

• Technician B

• Both

• Neither

With the brakes applied on a vehicle with power brakes, the pedal drops 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.

Who do you agree with?

• Technician A

• Technician B

• Neither

• Both

When performing a vacuum booster function test, start by pumping the brake pedal several times_________________________

• With the engine off

• With the engine running

• With the vacuum hoses removed

• While driving the vehicle slowly