Deck 94: Brake Hydraulic Systems

Question 1

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Answer 1

Both technicians A and B

Question 2

If the brake pedal linkage is not adjusted correctly, brake fluid may not be able to expand back into the reservoir through the ________ of the master cylinder when the brakes get hot.

A)Vent port (forward hole)
B)Replenishing port (rearward hole)

Answer 2

Vent port (forward hole)

Question 3

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Answer 3

Technician A only

Question 4

Two technicians are discussing a problem where the brake pedal travels too far before the vehicle starts to slow. Technician A says that the brakes may be out of adjustment. Technician B says that one circuit from the master cylinder may be leaking or defective. Which technician is correct?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 5

Air in the lines will cause what type of problem?

A)Low spongy brake pedal
B)Brake noise
C)Vibration in the brake pedal during stops
D)Hard brake pedal

Question 6

The master cylinder is able to move about how much brake fluid during each brake application?

A)50 ml
B)One tablespoon
C)One teaspoon
D)One cu. in.

Question 7

Brake fluid pressure is measured in what unit?

A)Pounds
B)Sq. in.
C)Inches
D)PSI

Question 8

How much brake fluid is in a typical master cylinder reservoir?

A)Enough to allow all brakes to become completely worn
B)15 to 20 liters
C)One pint
D)One gallon

Question 9

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?

A)Vent valve
B)Rubber diaphragm or floating disc
C)Residual valve
D)Compensating port

Question 10

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 11

The rubber used in most brake system components will swell if exposed to ________.

A)Moisture in the air
B)Engine oil or ATF
C)Water
D)DOT 5 brake fluid

Question 12

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 13

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 14

When cleaning hydraulic brake parts, use ________.

A)Denatured alcohol
B)Clean brake fluid
C)Either A or B
D)Neither A nor B

Question 15

Brakes that drag or fail to release can be caused by a ________.

A)Plugged vent port (compensating port)
B)Leaking primary cup
C)Failure of the residual pressure (check) valve
D)Leaking secondary cup

Question 16

Technician A says that the primary seal of the secondary piston is leaking if fluid is seen leaking from the rear of the master cylinder. Technician B says that air in the brake lines will cause a low brake pedal. Which technician is correct?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 17

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 18

Self apply of the brakes can occur if ________.

A)The master cylinder is overfilled
B)The vent port is clogged or covered
C)The replenishing port is clogged or covered
D)Both A and B

Question 19

Technician A says that the brake pedal height should be checked as part of a thorough visual inspection of the brake system. Technician B says that the pedal free play and pedal reserve should be checked. Which technician is correct?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 20

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 21

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

Question 22

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

Question 23

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 24

Master cylinder covers must be vented to ________.

A)Allow air to enter the system
B)Create a vacuum
C)Allow fluid to escape when it heats up
D)Avoid creating a vacuum

Question 25

The master cylinder body is NOT equipped with a ________.

A)Compensating port
B)Cylinder bore
C)Replenishing port
D)Transfer port

Question 26

If 200 psi of hydraulic pressure is applied to a two-square-inch caliper piston, the brake application force on a one-square-inch piston will be

A)400 psi
B)200 psi
C)100 psi
D)300 psi

Question 27

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?

A)Technician A only
B)Technician B only
C)Both technicians A and B
D)Neither technician A nor B

Question 28

The quick-take-up valve controls ________.

A)Fluid flow to and from the primary low-pressure chamber
B)Fluid flow between the primary and secondary high-pressure chambers
C)Fluid flow between the reservoir and the secondary low-pressure chamber
D)Fluid flow between the primary low and high-pressure chambers

Question 29

Identify the vent ports.

A)Either 1 or 2
B)1
C)Neither 1 nor 2
D)2

Question 30

What action of the master cylinder is illustrated below?

A)Brakes being released
B)Brakes at rest
C)Brakes being applied
D)None of these

Question 31

What service is being performed in this illustration?

A)Bench bleeding of a master cylinder
B)Lubricating a master cylinder before installation
C)Testing master cylinder pressures
D)Honing a master cylinder