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. Although these practice tests will prepare you for your state Commercial Driver License it is important to refer to your book. Please refer to your state Commercial Drivers License study guide for answers that may differ from the practice test. In the event that your state booklet has a different answer then your practice test please refer to your state booklet for the correct answer.

Air Brake Test 02

1 / 30

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

2 / 30

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

3 / 30

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

4 / 30

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

5 / 30

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

6 / 30

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

7 / 30

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

8 / 30

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

9 / 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?

10 / 30

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

11 / 30

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

12 / 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?

13 / 30

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

14 / 30

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

15 / 30

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

16 / 30

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

17 / 30

What is another name for 'squeeze' braking?

18 / 30

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

19 / 30

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

20 / 30

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

21 / 30

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

22 / 30

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

23 / 30

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

24 / 30

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

25 / 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?

26 / 30

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

27 / 30

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

28 / 30

Which of these applies to vehicles with automatic slack adjusters?

29 / 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...?

30 / 30

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

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Air Brakes Test

Getting a commercial driver’s license (CDL) is no different from getting your regular driver’s license. However, it is important to understand that a CDL has restrictions and one of them is the air brake restriction. This means that you cannot drive a vehicle equipped with this type of brakes unless you have passed a written air brakes test and have your skills tested on the road with a vehicle equipped with these brakes. Here is all you need to know about getting air brakes endorsement on your commercial driver’s license.

There are three types of CDL classes that determine the type of vehicle you may drive and how much you may tow. A Class A CDL class allows you to operate a vehicle with a GCWR of 26,001 if the vehicle you tow weighs more than 10,000 and a Class B CDL allows you to operate a vehicle with a GVWR of 26,001 or more pounds or operate any vehicle towing another vehicle that weighs less than 10,000 GVWR. With a Class C CDL, you can operate a Class C vehicle that transports hazardous materials.