hydraulic powerbooster quiz

Question 1

All of the air must be removed from a hydraulic brake system primarily because:

air will contaminate the brake fluid.

air will compress under pressure.

air will cause brakes to grab.

air will result in erratic braking.

Answer 1

air will compress under pressure.

Question 2

Stepping on the brake pedal moves the lip of the primary cup past the compensating port which causes:

a loss of hydraulic pressure in the reservoir causing the brakes to drag.

a continuous buildup of pressure in front of the primary cup.

a continuous buildup of pressure behind the secondary piston cup.

the pressure differential valve to shift in its bore and light the light on the dash.

Answer 2

a continuous buildup of pressure in front of the primary cup.

Question 3

When the brake circuit served by the primary section of the master cylinder has failed on a dual master cylinder system. How is the piston in the secondary circuit moved in it’s bore?

Hydraulic pressure from the primary circuit moves the secondary piston in its bore.

The secondary circuit is moved in it’s bore mechanically by the stem of the primary piston.

Through a mechanical connection between the secondary piston and the input push rod.

Through a hydraulic connection with the input push rod and the secondary piston.

Answer 3

The secondary circuit is moved in it’s bore mechanically by the stem of the primary piston.

Question 4

What is the purpose of bleeding the brakes?

To remove low pressure areas from the circuit to prevent cavitation.

To remove excess fluid from the circuit.

To relieve excess pressure that has built up in the circuit.

To remove air from the circuit.

Answer 4

To remove air from the circuit.

Question 5

Where is the metering valve located in a disc/drum brake system?

The metering valve is located in the drum circuit near the master cylinder.

The metering valve is located in the disc circuit after the pressure differential valve.

The metering valve is located in the drum brake circuit after the pressure differential valve to maintin pressure in the wheel cylinders to prevent leakage.

The metering valve is a special splitter valve used in diagonal split brake circuits.

Answer 5

The metering valve is located in the disc circuit after the pressure differential valve.

Question 6

What could be the cause of a low, soft/spongy brake pedal?

A failed brake boost unit could cause a low soft/spongy brake pedal.

water in the brake fluid could cause the brake pedal to be low and soft/spongy.

Air in the hydraulic brake fluid could cause the brake pedal to be low and soft/spongy.

A siezed caliper or wheel cylinder could cause the brake pedal to be low and soft/spongy.

Answer 6

Air in the hydraulic brake fluid could cause the brake pedal to be low and soft/spongy.

Question 7

A damaged master cylinder primary cup would be evident by:

fluid leaking at the rear of the master cylinder.

the brake pedal could be pushed slowly to the floor boards.

the brakes dragging due to the fluids inability to return to the reservior.

there would not be any residual pressure maintained in the rear brake circuit.

Answer 7

the brake pedal could be pushed slowly to the floor boards.

Question 8

In the disc (front), drum (rear), type of braking system rear wheel lock-up is prevented by:

a residual valve in the drum circuit.

the pressure diferential valve.

a proportioning valve as part of a combination valve.

a metering valve as part of the combination valve.

Answer 8

a proportioning valve as part of a combination valve.

Question 9

The brake shoe located toward the front on a servo brake system is often called:

the secondary shoe because it does not do as much work going forward.

the primary shoe because it is the first to contact the drum.

the first shoe because it is the one you mount to the backing plate first.

the servo shoe because it forces the other shoe into the drum when traveling forward.

Answer 9

the primary shoe because it is the first to contact the drum.

Question 10

Brake fade is caused by:

a grease/oil soaked brake lining.

the lining becoming overheated.

contaminated brake fluid.

poorly adjusted brakes.

Answer 10

the lining becoming overheated.

Question 11

What is one thing that is often necessary to do when removing a brake drum?

It may be necessary to remove the backing plate.

It may be necessary to heat the drum enough to expand and come off.

It may be necessary to back off the adjuster link.

It may be necessary to crack the bleeder screw and let off the residual pressure.

Answer 11

It may be necessary to back off the adjuster link.

Question 12

The primary reason power brake boosters were developed:

to reduce the size and weight of the hydraulic brake components.

to increase safety throug reduced brake failures.

to increase braking force and reduce operator fatigue.

to allow the use of disc brakes.

Answer 12

to increase braking force and reduce operator fatigue.

Question 13

What tool is used to check for brake rotor thickness variation (parallelisim)?

A vernier micrometer.

A dial indicator.

A vernier caliper.

A thickness gauge.

Answer 13

A vernier micrometer.

Question 14

What could be the cause of a pulsating brake pedal?

a)

Parallelisim beyond specification.

b)

A distorted/out of round drum.

c)

Excessive disc run out.

d)

The ABS circuit.

Answer 14

all the answer

Question 15

If the brake pedal drops slightly when the engine is started on a system that has power brakes, what would this indicate?

a)

Normal system operation.

b)

The boost unit is faulty.

c)

Damaged piston cups in the master cylinder.

d)

Not enough clearance on the input push rod.

Answer 15

Normal system operation.

Question 16

What is the primary function of the acumulator in a hydroboost system?

a)

To prevent pressure drops in the brake system.

b)

To dampen pressure spikes.

c)

To provide a reactionary component for brake application.

d)

To provide an additional 2 - 3 brake applications.

Answer 16

To provide an additional 2 - 3 brake applications.

Question 17

The hydro-boost system uses:

a)

engine oil pressure to boost the input force to the master cylinder.

b)

transmission oil pressure to boost the input force to the master cylinder.

c)

power steering oil pressure to boost the input force to the master cylinder.

d)

boost oil pressure to boost the input force to the master cylinder.

Answer 17

power steering oil pressure to boost the input force to the master cylinder.

Question 18

Before removing any lines from a Hydro-boost system, it is important that:

a)

the system pressure is relieved.

b)

all of the fluid is drained.

c)

the brakes are bled.

d)

all of the brakes are disassembled.

Answer 18

the system pressure is relieved.

Question 19

What would be the complaint if the self adjusters in drum brakes failed to operate?

a)

A spongy brake pedal

b)

A pulsating prake pedal.

c)

A high hard brake pedal.

d)

A low brake pedal.

Answer 19

d)

A low brake pedal.

Question 20

How is a vacuum suspended brake booster applied?

a)

By closing the air valve and the vacuum valve.

b)

By opening the air valve and opening the vacuum valve.

c)

By opening the vacuum valve and closing the air valve.

d)

By closing the vacuum valve and openin the air valve.

Answer 20

By closing the vacuum valve and openin the air valve.

Question 21

Air flows into a vacuum suspended brake booster:

a)

to apply the brakes.

b)

to release the brakes.

c)

to hold the brakes.

d)

for testing the operation.

Answer 21

a)

to apply the brakes.

Question 22

The energy of braking is converted to:

a)

various gasses.

b)

torque.

c)

heat.

d)

smoke.

Answer 22

c)

heat.

Question 23

You as a technician have to worry about public safety issues when working on brake systems?

a) True
b) False

Answer 23

a) True

Question 24

In a hydraulic over hydraulic system, if the main hydraulic pressure source were to fail, braking could still be accomplished with some boost by:

a)

an accumulator located on the booster unit.

b)

an electro-hydraulic pump connected to the booster unit.

c)

the use of a priority valve on the power steering pump.

d)

a or b

Answer 24

d)

a or b

Question 25

If lines need to be disconnected on a power brake booster, the safest method to make sure no pressure is in the system is to:

a)

bleed one of the wheel cylinders.

b)

open the bleeder on the master cylinder.

c)

drain the oil from the power steering pump.

d)

pump the pedal 4 or 5 times with the key off.

Answer 25

d)

pump the pedal 4 or 5 times with the key off.

Question 26

In a vacuum suspended brake booster, a leaking check valve on the vacuum supply line would:

a)

prevent any boost from occurring during application with the engine off.

b)

prevent full boost from occurring with the engine running.

c)

cause the brakes to drag when they are released.

d)

prevent any boost from occurring with the engine running.

Answer 26

prevent any boost from occurring during application with the engine off.

Question 27

If a hydraulic brake booster is used on a system where there is air in the brake lines going to the wheel cylinders, the result would be?

a)

No brakes would apply.

b)

We would have normal brakes but no boost.

c)

We would have a spongy pedal when the brakes are not applied

d)

We would have spongy brake pedal feel with a boost.

Answer 27

We would have spongy brake pedal feel with a boost.

Question 28

Vacuum boosters work because a difference exists between a low pressure area and a high pressure area.

a) True
b) False

Answer 28

a) True

Question 29

Air used in the air-over-hydraulic booster system is:

a)

atmospheric air pressure.

b)

vacuum pressure.

c)

vented air pressure.

d)

compressed air.

Answer 29

d)

compressed air.

Question 30

When bleeding the brakes in an air-over-hydraulic system should:

a)

proceed normally.

b)

use a power booster.

c)

reduce air system pressure.

d)

a or b

Answer 30

reduce air system pressure.

Question 31

what would be the pressure developed in the brake system if a 100N force was applied to a master cylinder piston that is 10cm2 ?

a)

100 Pa

b)

100 kPa

c)

10 000 Pa

d)

10 000 kPa

Answer 31

b)

100 kPa

Question 32

All the brakes drag on a truck equipped with hydraulic drum brakes. The cause of this condition could be:

a)

a seized metering valve.

b)

insufficient brake pedal free travel.

c)

a leaking primary cup seal in the master cylinder

d)

a pinched brake line to the rear brakes.

Answer 32

insufficient brake pedal free travel.

Question 33

The electric brake controller should be adjusted:

a)

initially as well as when the load changes and road conditions change.

b)

initially only.

c)

to do most of the braking.

d)

then mounted out of sight.

Answer 33

initially as well as when the load changes and road conditions change.

Question 34

When adjusting a park brake your final adjustment is:

a)

service brakes.

b)

pedal height.

c)

pushrod clearance.

d)

cable.

Answer 34

d)

cable.

Question 35

In a hydraulically operated parking brake system, the hydraulic fluid is used to:

a)

cage a spring which applies the brake.

b)

apply pressure on the wheel cylinders to apply brakes for parking.

c)

increase pressure being applied to the master cylinder.

d)

force a spring to apply the brakes.

Answer 35

cage a spring which applies the brake.

Question 36

Parking brakes are all:

a)

mechanically applied release method varies.

b)

application varies mechanically released.

Incorrect Response
c)

manually applied release varies.

d)

designed for effective emergency use.

Answer 36

a)

mechanically applied release method varies.

Question 37

In an emergency situation the electric trailer brakes will be able to provide the total braking requirements needed by the truck and trailer combination.

a) True
b) False

Answer 37

b) False

Question 38

When a conductor to the trailer brake electromagnet is broken the brake:

a)

will not function with normal application but will work if the brakeaway is engaged.

b)

will not function.

c)

will still function normally as long as one wire is connected.

d)

will function under normal conditions but will not function if the brakeaway is engaged.

Answer 38

will not function.

Question 39

When using an ammeter to check the trailer brakes, a high amperage draw reading could indicate:

a)

a short circuit in the electromagnet.

b)

a wire size too small for the application.

c)

a broken wire in the circuit.

d)

an open circuit.

Answer 39

a short circuit in the electromagnet.

Question 40

Dot 5 brake fluid is commonly used with ABS systems.

a) True
b) False

Answer 40

b) False

Question 41

The auxillary battery on the trailer is used for:

a)

normal braking.

b)

emergency and normal braking.

c)

a safety in case the trailer and tow vehicle become disconnected.

d)

backup in case the tow vehicle battery voltage is too low.

Answer 41

a safety in case the trailer and tow vehicle become disconnected.

Question 42

The driveshaft parking brake, when applied, will be ineffective if:

a)

the engine is not running.

b)

the hydraulic brake system is leaking.

c)

one wheel is lifted.

d)

all of the above.

Answer 42

one wheel is lifted.

Question 43

In an electric brake system, resistance in the connector between the tractor and trailer will:

a)

cause the brakes to apply to hard.

b)

increase the current flow above what it should be.

c)

not allow the brakes to apply at all.

d)

reduce the amount of voltage going to the electromagent.

Answer 43

d)

reduce the amount of voltage going to the electromagent.

Question 44

One of the more common areas for problems in parking brake systems is:

a)

use in cold weather.

b)

seizing of parking brake cables.

c)

hydraulic system leaks

d)

wear of friction materials.

Answer 44

seizing of parking brake cables.

Question 45

In an electric trailer brake system, the brake application is controlled by:

a)

varing voltage to the electromagents.

b)

varing resistance of the electormagents.

c)

removing the electromagnets.

d)

applying hydraulic pressure to the electormagnet.

Answer 45

varing voltage to the electromagents.

Question 46

Before adjusting the parking brake mechanism we should always:

a)

make sure the parking brake is applied.

b)

disconnect the battery.

c)

make sure the service brakes are adjusted.

d)

adjust the cable tension first.

Answer 46

make sure the service brakes are adjusted.

Question 47

Park brake cable adjustment can only be done at the control mechanism.

a) True
b) False

Answer 47

b) False

Question 48

For the brakeaway or emergency system to work properly, we must make sure that the:

a)

brakeaway switch is disconnected before using the trailer.

b)

brake lights are not burnt out.

c)

trailer connection to the hitch has a lock on it.

d)

trailer battery is charged.

Answer 48

d)

trailer battery is charged.

Question 49

When going through a parking brake adjustment procedure, we should always:

a)

set shoe or band to drum clearance last.

b)

bleed the brakes first.

c)

adjust the cable last.

d)

remove the shoe or band to make sure they are seated.

Answer 49

c)

adjust the cable last.

Question 50

Drive line brakes are:

a)

self-adjusting.

b)

affected by road spray.

c)

only used for emergencies.

d)

adjusted from inside the cab.

Answer 50

b)

affected by road spray.

Question 51

The most common problem with electric brake systems is:

a)

worn foundation brake parts.

b)

poor electrical connections.

c)

leakage of oil or brake fluid into the foundation brakes.

d)

seized cables.

Answer 51

poor electrical connections.