Air Brake Test

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Air Brakes Test

1 / 70

Brake drums...

Are bolted to the wheels

Are located at each end of the vehicle's axles

Hold the brake shoes and linings

All of the above

2 / 70

When the low pressure warning is activated, you should...

Wait for the air brakes to come on automatically

Bring the vehicle to a safe stop while you still control the brakes

Monitor your air pressure gauge and maintain highway speeds

Pump the brake pedal hard to stop

3 / 70

When the safety valve releases air it means that...

The pressure has exceeded 150 psi

Too much air is in the air compressor

Something is wrong, and you should have it checked by a mechanic

All of the above

4 / 70

In a single vehicle with a fully charged air system, air pressure loss (after the initial drop and brake applied) should be less than...

2 psi per minute

3 psi per minute

4 psi per minute

none of the above

5 / 70

The service brake system...

is an official vehicle inspection

applies and releases the brakes by using the brake pedal under normal driving

are the valves that keeps the air tank pressure serviced

is only on vehicles with hydraulic brakes

6 / 70

Your vehicle's single brake system needs adjustment if...

pressure builds from 50 to 75 psi within three minutes

pressure builds from 85 to 100 psi within 45 seconds

the compressor cuts out between 70 to 90 psi

the governor stops between 75 to 90 psi

7 / 70

Some air brake systems have an alcohol evaporator which helps...

Reduce the risk of ice in the air brake valves during cold weather

Remove oil from the air lines

Reduce the risk of water in the air brake valves in warm weather

Remove fuel from the air lines

8 / 70

Air tanks should be drained...

Once a week

Once a day

Every four hours

Every two or three days

9 / 70

The safety valve in the air compressor tank is set to open at...

150 psi

200 psi

100 psi

175 psi

10 / 70

Compressed air is stored...

In the hoses

In the engine compartment

In the fuel tank

In the storage tank

11 / 70

The Air Compressor Governor controls...

When the brakes should be applied

When the air compressor pumps air into the storage tanks

When the warning light is activated

When the air is released from the tank

12 / 70

A dual air brake system...

Has two air brake systems and one set of controls

Takes less time to build air pressure

Has one set of air tanks and hoses

Must have two warning alarms

13 / 70

An emergency brake...

Is required on commercial vehicles

Must be held on by mechanical force

Could be activated by the loss of air pressure

All of the above

14 / 70

To check the slack adjusters on S Cam brakes, you should...

Leave the parking brakes on and pull on the slack adjuster

Wear gloves and pull hard on each slack adjuster

Make sure the slack adjusters move more than one inch each way

Drain the air from the system and pull on the slack adjusters

15 / 70

To test the low pressure warning signal, you should do all BUT the following...

Shut the engine off

Turn the electrical power on

Ask a friend to listen for the signal

Step on and off the brake pedal to reduce air pressure

16 / 70

With dual air systems, the air pressure should build...

From 85 to 100 psi in 45 seconds

From 70 to 100 psi in 60 seconds

From 85 to 150 psi in 45 seconds

From 70 to 150 psi in 60 seconds

17 / 70

A fully charged air system typically has ____ psi.

100

125

150

175

18 / 70

To test the air leakage rate you should...

Leave the engine running and release the service brake

Turn off the engine and release the service brake

Charge the air system and leave the engine running

Depress the brake pedal and monitor the air pressure gauge

19 / 70

When testing air leakage rates for combination vehicles (before applying the brake pedal), air brake systems should not lose air faster than...

2 psi per minute

3 psi per 30 seconds

3 psi per minute

4 psi per minute

20 / 70

To check the air compressor governor "cut in" and "cut out" pressures...

Run the engine at a fast idle

Step on and off the brake to reduce tank pressure

Monitor the air pressure gauge

All of the above

21 / 70

Air tanks should be drained...

at the end of each day or shift

to keep sludge from clogging brake system valves

manually when automatic devices fail

all of the above

22 / 70

Fanning air brakes...

cools them off

increases the air pressure

increases the braking power

decreases the air pressure

23 / 70

If your air compressor stops working...

you will lose your brakes immediately

the brakes will immediately lock up

you'll still have air pressure left in the air tanks

your brakes won't be affected

24 / 70

The governor allows the air to start pumping again when it reaches the cut in level, or around...

200 psi

100 psi

150 psi

125 psi

25 / 70

You should not use the parking brakes...

on a steep hill

if the air pressure is low

when the brakes are hot

in hot weather

26 / 70

The brake drums or discs...

must have linings that fit loosely on the brake shoes

must not have any cracks

must not have cracks longer than half the width of the friction area

should be kept well-greased

27 / 70

Slack adjusters...

never need to be adjusted

should only be adjusted by a qualified mechanic

can be adjusted manually or automatically

should travel at least two inches from where the push rod is attached

28 / 70

To determine if slack adjusters need adjustment...

apply the service brakes and release the parking brakes

apply both the service and parking brakes

pull out the automatic slack adjustment control knob

release both the service and parking brakes

29 / 70

An air tank is equipped with a drain valve to remove...

Air and water

Oil and air

Water and oil

Dirt and oil

30 / 70

The governor stops pumping air when it reaches the "cut out" level, or around...

125 psi

200 psi

225 psi

175 psi

31 / 70

Air loss in a straight truck or bus should not be more than ____ with the engine off and the brakes released.

1 psi in 30 seconds

1 psi in one minute

2 psi in one minute

3 psi in one minute

32 / 70

To make an emergency stop with air brakes, using the stab braking method, you should:

Pump the brake pedal rapidly and lightly.

Brake hard until the wheels lock, and then get off the brakes for as much time as the wheels were locked

Brake as hard as you can, get off the brakes when the wheels lock, get back on the brakes when the wheels start rolling again.

Press hard on the brake pedal and apply full hand valve until you stop.

33 / 70

You should know that your brakes are fading when:

Pressure on the brake pedal is released and speed increases.

You have to push harder on the brake pedal to control your speed on a downgrade.

The brake feels spongy when pressure is applied

Less pressure is needed on the brake pedal for each stop

34 / 70

To check the free play of manual slack adjusters on s-cam brakes you should:

Park on level ground, chock the wheels, and release the parking brakes.

Stop on level ground and apply the parking brakes.

Park on level ground and drain off air pressure before adjusting.

Park on a slight grade, release the parking brake, apply the service brakes, and check for vehicle movement.

35 / 70

If the air compressor should develop a leak, what keeps the air in the tanks?

The tractor protection valve

The emergency relay valve

The one way check valve

The air compressor

36 / 70

When driving down a long steep hill you should:

Use stab braking.

Begin braking when you are 10 M.P.H. above your safe speed.

Release the brake when you are 5 M.P.H. below your safe speed.

Use the trailer brakes.

37 / 70

The brake system that applies and releases the brakes when the driver uses the brake pedal is the:

Service brake system.

Emergency brake system.

Parking brake system.

None of the above.

38 / 70

The most common type of foundation brakes found on heavy vehicles is the:

Disc brakes

Wedge drum

S-cam drum

None of the above

39 / 70

Vehicles with air brakes must have:

At least two air tanks.

An air pressure gauge to show the pressure available for braking.

An air pressure gauge, to show air used by the brake chambers for braking.

None of the above.

40 / 70

The driver must be able to see a warning that is given before air pressure in the service air tanks falls below:

80 psi

40 psi

20 psi

60 psi

41 / 70

If your vehicle has an alcohol evaporator, every day during cold weather you should:

Clean the air filter with alcohol.

Check and fill the alcohol level.

Change the alcohol from a new bottle.

Check the oil for alcohol content.

42 / 70

During normal driving, spring brakes are usually held back by:

Spring pressure

Bolts or clamps

Centrifugal force

Air pressure

43 / 70

Air braking takes more time than hydraulic braking because air brakes:

Need to have airflow through the lines to work.

Use different brake drums.

Require heavier return springs.

All of the above.

44 / 70

In air brake vehicles, the parking brakes should be used:

To hold your speed when going downhill.

Whenever the vehicle is parked.

As little as possible.

Only during pre and post trip inspections.

45 / 70

The brake pedal in an air brake system:

Is to be used as a footrest during normal driving.

Controls the speed of the air compressor.

Controls the air pressure applied to put on the brakes.

Is connected to slack adjusters by a series of rods and linkages.

46 / 70

If your truck or bus has dual parking control valves it means that you can use pressure from a separate tank to:

Balance the service brake system.

Release the spring brakes to move a short distance.

Stay parked without using up service air pressure.

Apply more brake pressure if the main tank is getting low.

47 / 70

A straight truck or bus air brake system should not leak at a rate of more than ____ PSI per minute with the engine off and the brakes released.

48 / 70

If your vehicle has an alcohol evaporator, it is there to:

Reduce the risk of ice in air brake valves in cold weather.

Eliminate the need for daily tank draining.

Rid the wet tank of alcohol that condenses and sits at the bottom.

Boost tank pressure the same way that superchargers boost.

49 / 70

If you must make an emergency stop, you should brake so that you:

Use the full power of the brakes and lock them.

Can steer hard while braking hard.

Stay in a straight line and can steer.

Use the hand brake first.

50 / 70

Your truck or bus has a dual air brake system. If a low air pressure warning comes on for only one system, what should you do?

Reduce your speed and drive to the nearest garage for repairs.

Continue at normal speed and find a garage before the brakes lock.

Reduce your speed and test the remaining system while under way.

Stop. Safely park, and continue only after the system is fixed.

51 / 70

When you apply pressure to the brake pedal, you are...

Putting on the brakes

Releasing air pressure to the brakes

Reducing air in the tanks

Activating the safety valve

52 / 70

The air compressor is connected to the engine through...

Gears

Hoses

V-Belt

Gears or a v-belt

53 / 70

Which type of brake is the most common in commercial vehicles?

Wedge brakes

Disk brakes

S Cam brakes

Drum brakes

54 / 70

An application pressure gauge...

Shows how much air pressure you are applying to the brakes

Is connected to the generator

Releases air when you accelerate

Prevents brake failure

55 / 70

All vehicles with air brakes are required to have a low pressure warning signal. This could be...

A red light

A wig wag mechanical arm

A buzzer

Any one of the above

56 / 70

To test your service brakes you should...

Stop the vehicle and put the parking brake on

Release the parking brake, move forward slowly and depress brakes

Put parking brake on and release air pressure

Depress brakes when traveling at highway speeds

57 / 70

Stab braking occurs when you...

Press on the brake pedal as hard as you can

Release the brakes when the wheels lock up

Apply the brakes when the wheels start rolling

All of the above

58 / 70

Air brakes take longer to stop than hydraulic brakes because...

The reaction time is longer for the driver

It takes longer for the air to flow through the lines

The linings get hotter more quickly

None of the above

59 / 70

The proper way to go down long grades is to...

Use a low gear and push hard on the brakes

Let up on the brakes from time to time to cool them

Use a low gear and apply constant, light pressure on the brakes

Apply brakes just hard enough to reduce speed to five mph below safe speed then release until back to safe speed and repeat process.

60 / 70

You should avoid using the parking brake...

on steep hills

if the air pressure is low

when the brakes are hot

any time you park

61 / 70

Modern air brake systems combines three different systems. The are the service brakes, the parking brakes and the:

S-cam brakes.

Drum brakes.

Foot brakes.

Emergency brakes.

62 / 70

Oil and water usually collect in compressed air tanks. If you do not have an automatic tank drain, when should you drain the air tanks?

After every working day.

After every four hours of service.

Once a week.

Every other week.

63 / 70

Why drain water from the compressed air tanks?

To keep from fouling the air compressor oil.

Water can freeze in cold weather and cause brake failure.

The low boiling point of water reduces braking power.

Water over cools the compressor.

64 / 70

Air brake equipped vehicles must have:

A supply pressure gauge.

An air use gauge.

At least two brake heaters.

A backup hydraulic system.

65 / 70

What can legally hold a parking or emergency brake in position for a truck, truck tractor or bus?

Fluid pressure

Air pressure

Spring pressure

Any of the above

66 / 70

Which of the following makes the total stopping distance for air brakes longer than that for hydraulic brakes.

Brake lag distance.

Action distance.

Perception distance.

Effective braking distance.

67 / 70

Of the choices below, the first thing to do when a low air pressure warning comes on is:

Open the air supply control valve.

Adjust the brake pedal for more travel.

Stop and safely park as soon as possible.

Up-shift.

68 / 70

The braking power of the spring brakes:

Can only be tested by highly trained brake service people.

Depends on the adjustment of the service brakes.

Increases when the service brakes are hot.

Is not affected by the condition of the service brakes.

69 / 70

The air compressor governor controls:

When air is pumped into the air tanks.

Air pressure applied to the brakes.

The speed of the air compressor.

When the brake chambers release pressure.

70 / 70

The application pressure gauge shows the driver how much pressure:

Has been used on the trip.

Is in the air tanks.

None of these.

s being applied to the brakes.

Your score is

The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake test.

There are two parts to the air brake endorsement test – the written and the practical part. The written portion consists of 20 to 25 multiple-choice questions; this test is administered on a computer. The number of questions might vary depending on the state. Usually it is 20-25 questions. The pass mark for the written exam is 80%. Some of the important contents for the written exam includes:

Components of an air brake system and dual air brakes.
Inspection of the air brake system.
The safe use of air brakes.

For first-time CDL drivers, the knowledge exam is included in the skill test. Those adding an endorsement to their CDL will have to schedule their skill test through their local licensing office. The essence of the practical exam is to ensure that you can safely use air brakes.

To pass the practical test (skills test), you will have to demonstrate that you are good at:

Using appropriate pressure for different tasks
Building air pressure
Releasing brakes
Testing low air and,
Gauging air pressure

Take this CDL practice test now to prepare for the actual air brakes test.