AIR BRAKES TEST – 02

The Commercial Driver License Air Brakes Practice Test is designed to help you prepare for the state test. With this practice test, your knowledge will be challenged. These practice test questions are designed to see where you stand before you take your CDL. These tests will let you know what areas you will need to improve on.

Air Brake Test 02

1 / 30

Which of these applies to vehicles with automatic slack adjusters?

They can be checked less often

They don't need checking at all

Any of these depending on age of vehicle

They must be checked just as often

2 / 30

Before you check the slack adjusters on S-cam brakes, you should...?

Wedge the foot brake

Turn on the engine

Chock the wheels

Apply the parking brake

3 / 30

In a dual air brake system, the 'primary' system will usually operate the regular brakes on...?

The front axle

The rear axle or axles

Both axles

Any of these

4 / 30

If the pressure in a dual air system drops below 60 psi for one system but stays normal for another, you should...?

Stop immediately and have it fixed

Continue driving as normal

Have it fixed the next time the vehicle is not being used

Have it fixed at the next routine maintenance

5 / 30

If on an automatic slack adjuster the push rod stroke exceeds the legal brake adjustment limit, it indicates that...?

There is a problem with the brake components

The adjuster was improperly installed

Any of these might be the problem

The adjuster is broken

6 / 30

A dual air brake system has how many separate air brake systems?

Four

Three

Two

One

7 / 30

The proper method of braking while going down long of steep curves after selecting the proper gear is to brake until your speed drops to _____mph below the safe speed then release your brakes?

8 / 30

If air hoses connected to brake chambers are cut or worn, they should be...?

Taped up

Replaced

Noted on your report

Any of these depending on circumstances

9 / 30

The air loss rate for a straight truck or bus with engine off and brakes on, should not be more than:

4 p.s.i. in 45 seconds

2 p.s.i. in 45 seconds

5 p.s.i. in 30 seconds

1 p.s.i. in 60 seconds

10 / 30

You should test the low pressure warning signal with...?

Engine on and electrical system on

Engine off and electrical system off

Engine off and electrical system on

Engine on and electrical system off

11 / 30

The best way to find out if a vehicle built before ABS was a mandatory requirement is equipped with the system is to...?

Look at the rear of the vehicle

Test the brakes at speed

Look under the vehicle

Look on top of the vehicle

12 / 30

Vehicles will have automatic slack adjusters if they were built since...?

1991

2000

1994

1997

13 / 30

If the low-pressure warning signal does not work properly, what should you do?

Note it on your report

Schedule it for fixing at the next routine maintenance

Not drive until it is fixed

Ignore it

14 / 30

The most common flaw found in roadside inspections of air brake systems is...?

Worn brake shoes

Worn brake linings

Broken springs

Out of adjustment brakes

15 / 30

On older ABS systems, the malfunction lamp may not go out until you exceed...?

20 mph

5 mph

15 mph

10 mph

16 / 30

During the engine compartment check part of your inspection procedure on an air brake equipped vehicle you should check...?

The air hoses

The air compressor drive belt

The springs

The oil levels

17 / 30

Before driving a vehicle with a dual air system you should allow the air compressor to build up a minimum of what pressure in both systems?

90 psi

100 psi

70 psi

80 psi

18 / 30

On tractors, trucks and buses, the ABS malfunction lamp will be found...?

On the gear lever

On the instrument panel

Behind the front bumper

On the steering wheel

19 / 30

In a dual air brake system the 'secondary' system will usually operate the regular brakes on...?

Both axles

The front axle

The rear axle or axles

Any of these

20 / 30

In dual air brake systems, which of these will be individual to each system?

All of them

Air lines

Air hoses

Air tanks

21 / 30

You have fully-charged air system (125). After turning off the engine and releasing the service brake, what is the maximum leakage rates per minute for both single and combination vehicles?

1 psi for single, 2 psi for combination

5 psi for single, 7 psi for combination

2 psi for single, 3 psi for combination

4 psi for single, 5 psi for combination

22 / 30

If your vehicle has ABS, your stopping distance compared to a non-ABS vehicle will be reduced by...?

20%

10%

30%

23 / 30

When you pull hard on a slack adjuster, it probably needs adjustment if it moves more than...?

1 inch

3 inches

Half an inch

2 inches

24 / 30

A trailer with ABS will have a malfunction lamp...?

At the rear

On the right side

In any of these places

On the left side

25 / 30

What is another name for 'squeeze' braking?

Foundation braking

Controlled braking

Spring braking

Emergency braking

26 / 30

If you find an automatic adjuster is outside the brake pushrod stroke legal limit, you should...?

Ask a mechanic to adjust it

Ask a mechanic to overhaul the brakes

Adjust it yourself

Ignore it

27 / 30

If you fan the brake pedal to reduce tank pressure with the engine off, the spring brakes should activate when the air pressure drops to...?

40 – 65 psi

50 – 75 psi

20 – 45 psi

30 – 55 psi

28 / 30

Under ideal conditions, a truck with air brakes going 55 miles per hour requires stopping distance of:

More than 600 feet

More than 500 feet

More than 400 feet

More than 300 feet

29 / 30

Air brake vehicles other than truck tractors will definitely have ABS if built after March 1...?

1996

2000

1998

1999

30 / 30

Brake drums or discs must not have cracks which are longer than what proportion of the width of the friction area?

30%

50%

60%

40%

Your score is

The CDL Air Brake test is meticulously crafted to assist you in preparing for your state’s official licensing examination. This practice test presents a variety of questions that challenge your understanding and knowledge of crucial topics related to air brakes, ensuring you are well-prepared for the rigors of the CDL test.

As you work through these questions, you will gain valuable insights into your current knowledge level and identify specific areas where improvement is needed. While these practice tests serve as a vital tool in your study regimen, it is essential to complement them with your official state Commercial Driver License study guide. This guide contains authoritative information that may differ from the practice test answers.

In cases where the practice test and your state’s study material conflict, always prioritize your state’s study material for the correct answers. For a comprehensive review and to further enhance your readiness, be sure to visit and take this CDL practice test tailored to your needs. This preparation will not only boost your confidence but also equip you with the skills necessary for a successful driving career.