Exam 94: Brake Hydraulic Systems

Technician A says that if brake fluid movement is observed when the service brake is depressed, there is air in the hydraulic system. Technician B says that if venting (compensating) occurs, the master cylinder is usually operating okay. Which technician is correct?

Technician A says that brake pedal freeplay may be as little as 1/8 inch. Technician B says that brake pedal freeplay allows the master cylinder pistons to fully retract. Which technician is correct?

The brakes on a vehicle work OK for a while, then the vehicle slows because the brakes self-applied. Technician A says that an overfilled master cylinder could be the cause. Technician B says that a blocked vent port (compensating port) could be the cause. Which technician is correct?

Technician A says that the brake fluid reservoir should be filled to the top of the reservoir to be assured of proper brake pressure when the brakes are applied. Technician B says that the brake fluid level should be filled only to the maximum level line to allow for expansion when the brake fluid gets hot during normal operation. Which technician is correct?

Two technicians are discussing overhauling master brake cylinders. Technician A says that the manufacturer may recommend replacement of the entire master cylinder assembly instead of an overhaul. Technician B says that many overhaul kits include replacement piston assemblies. Which technician is correct?

What service is being performed in this illustration?

Two technicians are discussing master cylinders. Technician A says that it is normal to see fluid movement in the reservoir when the brake pedal is depressed. Technician B says a defective master cylinder can cause the brake pedal to slowly sink to the floor when depressed. Which technician is correct?

Brake fluid pressure is measured in what unit?

Master cylinder covers must be vented to ________.

The diaphragm keeps the brake fluid from freezing in cold climates.

The quick-take-up valve controls ________.

Air in the lines will cause what type of problem?

What action of the master cylinder is illustrated below?

Some master cylinder pistons have holes drilled behind their seals to help fluid return.

What part in the master cylinder helps keep air from contacting the brake fluid yet allows the fluid level to drop as the disc brakes wear?

The primary brake circuit fails due to a leak in the lines, leaving the rear section of a dual split master cylinder. Technician A says that the driver will notice a lower than normal brake pedal and some reduced braking power. Technician B says that the brake pedal will "grab" higher than normal. Which technician is correct?

Two technicians are discussing the operation of a dual master cylinder. Technician A says that the push rod is connected to the primary piston. Technician B says that the secondary piston is pushed forward by the fluid trapped ahead of the primary piston. Which technician is correct?

Self apply of the brakes can occur if ________.

The master cylinder body is NOT equipped with a ________.

Technician A says that the vent port is open when the brakes are NOT applied. Technician B says that the replenishing port is open when the brakes are NOT applied. Which technician is correct?