CDL Air Brakes Test


This is the Commercial Vehicle Driver's License Test covering Air Brakes.  You will be presented with 40 questions and you must answer 34 questions correctly to pass.  There is no time limit.  You may not go back once you answer a question.  Click the "Start Quiz" button below to begin.  Good luck!

1 / 40

Should the air pressure in the service air tanks fall below____the driver must be alerted via warning mechanism in the truck cab.

2 / 40

After the initial drop, the maximum leakage rates per minute is:

3 / 40

How often should air tanks be drained?

4 / 40

The 3 parts of the air brake system are: service brakes, parking brakes, and ____.

5 / 40

When does stab braking occur?

6 / 40

The best way to test if the spring brakes come on automatically is to:

7 / 40

A slack adjuster is:

8 / 40

Select the true statement in regards to brake drums or discs:

9 / 40

Select the true statement about emergency brakes:

10 / 40

Select the purpose of fanning air brakes:

11 / 40

When should you drain air tanks that do not have an automatic tank drain?

12 / 40

The parking brakes should be used____in air brake vehicles.

13 / 40

Select the inappropriate way to test for the low pressure warning signal.

14 / 40

Select the true statement about slack adjusters:

15 / 40

Air tanks should be drained:

16 / 40

When does your vehicle's single brake system need an adjustment?

17 / 40

You should_____to make an emergency stop with air brakes when using the stab braking method.

18 / 40

____is what can legally hold the parking brake or emergency brake in position for a bus, truck, or truck tractor.

19 / 40

How do you determine if slack adjusters need to be adjusted?

20 / 40

Select how you would check the truck's slack adjusters.

21 / 40

You should brake on a long steep downgrade hill as a supplement to the braking effects of the engine

22 / 40

Select the true statement about tractor protection valve:

23 / 40

How do you test your service brakes?

24 / 40

What are slack adjusters?

25 / 40

How do you check the air compressor governor "cut in" and "cut out" pressures?

26 / 40

How often should you drain your air tanks?

27 / 40

Air tanks need to be drained:

28 / 40

The compressor is connected to the engine via _____?

29 / 40

A leak rate for a straight truck or bus air brake system should not exceed _____psi per minute when the engine is off and the brakes are released.

30 / 40

Front wheel brakes are good under what kind of conditions?

31 / 40

You should___to reduce the air leakage rate.

32 / 40

Select the true statement in regards to brake drums:

33 / 40

Select how you can tell if your vehicle is equipped with an anti-lock braking system:

34 / 40

You should_____when checking the slack adjusters on S-Cam brakes.

35 / 40

Alcohol evaporators in some air brake systems help to:

36 / 40

Select the true statement about dual air brake systems.

37 / 40

Is this statement true or false: you do not need to use the parking brake if are leaving your vehicle for a short amount of time.

38 / 40

The best way to test the low air pressure warning signal is to:

39 / 40

Select the answer that is not a part of the braking process when driving a tractor-trailer combination vehicle that has ABS:

40 / 40

Select the part that is not a part of the drum brake:

Your score is

The average score is 79%

5/5 - (1 vote)

CDL Category Practice Tests