CDL Air Brakes Practice Test – 01

We know that taking the air brakes test as part of your CDL permit can cause anxiety in even the most confident driver. That is why we designed this free CDL air brakes practice test so that you can practice and get an idea of what types of questions will be asked on the actual test at the DMV. We encourage you to take it as many times as you would like or until you get a perfect score. We hope that this practice test proves helpful as you study for your exam. Please visit us again and take all of our practice exams as often as you would like.

Air brake systems are three braking systems combined. They are:

Question 1 of 30

The stoplights on an air brake system are activated by...?

Question 2 of 30

In a wedge brake system, a push rod pushes a wedge directly...?

Question 3 of 30

The resistance you feel when you push the brake pedal down comes from...?

Question 4 of 30

When air is pumped into a brake chamber, what is the first thing that happens?

Question 5 of 30

Foundation brakes can be found on...?

Question 6 of 30

The most common sort of emergency and parking brake on large vehicles is...?

Question 7 of 30

The air compressor should stop pumping at about ____ P.S.I.

Question 8 of 30

On large buses, it is common for low-pressure warning devices to activate at around...?

Question 9 of 30

If the spring brakes are on you should push the brake pedal.

Question 10 of 30

Air tanks should be drained to clear them of...?

Question 11 of 30

The low air pressure warning signal on an air brake system must come on before the air pressure falls below...?

Question 12 of 30

The brake system that applies the use of the brakes when the driver uses the brake pedal is the ______ brake system?

Question 13 of 30

An air pressure system is fully charged at _____ P.S.I.?

Question 14 of 30

Supply pressure gauges on an air brake system tell you...?

Question 15 of 30

Pumping the brake pedal up and down unnecessarily can result in...?

Question 16 of 30

The application pressure gauge shows...?

Question 17 of 30

Brakes can stop working if...?

Question 18 of 30

On vehicles made before 1975, if the front brake limiting valve control is switched to 'slippery' the air pressure to the front brakes will be cut by...?

Question 19 of 30

If application pressure increases without a decrease in speed, you need to...?

Question 20 of 30

Drum brakes work by pressing brake shoes and linings against...?

Question 21 of 30

Air compressor governors are programmed to cut out when air pressure reaches around...?

Question 22 of 30

When the low air pressure warning light or buzzer comes on, you should...?

Question 23 of 30

Emergency brakes and parking brakes on all large vehicles must be operated by...?

Question 24 of 30

Safety relief valves on the first tanks are usually set to open at...?

Question 25 of 30

An air compressor governor will resume pumping air to the tanks when tank pressure falls below around...?

Question 26 of 30

Spring brakes are usually fully activated when the air pressure is between...?

Question 27 of 30

Many vehicles have automatic front wheel limiting valves, which will reduce air to the front brakes unless they are applied with a pressure of greater than...?

Question 28 of 30

Which of these brake systems uses a 'power screw'?

Question 29 of 30

You should drain air tanks at the end of...?

Question 30 of 30



Study CDL Air Brakes Practice Test and Applying for the for the Air Brake endorsement

When applying for the Air Brake endorsement taking a written test, the first thing to do is to verify that you meet the requirements for sitting for the written test. You should then verify the amount of fees you are required to pay as you apply.

You should then fill up the air brake endorsement written test application then turn it in. Schedule an appointment for the skills test. This should only be done after you are comfortable and ready for the test. To be ready, make sure you read the CDL handbooks and take this CDL air brakes practice test to find out if you’re ready for the actual written test.

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.


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