Air Brakes

This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice.. Read More

This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice questions. Each question has four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Indiana Commercial Driver License Manual. Questions come from the chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.

Number of Question
Passing Score

1. Truck tractors with air brakes built on or after March 1, 1997 must have:

Explanation
Truck tractors with air brakes built on or after March 1, 1997 must be equipped with Anti-Lock Braking Systems (ABS).

2. When inspecting your brakes, a slack adjuster should move ____ from where it is attached to the push rod.

Explanation
Check each slack adjuster after setting wheel chocks and disengaging the parking brake. Pull the slack adjusters to make sure they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

3. Water and compressor oil are usually found in the compressed air within an air brake system. Water and compressor oil:

Explanation
Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.

4. What is removed when an air tank is drained?

Explanation
In an air brake system, the air storage tanks are equipped with drains to allow water and compressor oil to be removed. The water and oil can damage the brakes if left to accumulate in the system.

5. To stop a vehicle using air brakes:

Explanation
To stop normally in a vehicle with air brakes, press down the brake pedal.

6. A dual air brake system:

Explanation
A dual air brake system has two separate air brake systems that use a single set of brake controls. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle.
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