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. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Georgia Commercial Driver’s Manual. Questions come from chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.

Number of Question
Passing Score

19. Why do you need to drain air tanks regularly?

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. Tanks must be drained regularly to remove this build-up.

20. The parking brake should be:

Explanation
The parking brake in a vehicle with air brakes should be used every time the vehicle is parked.

21. To use the stab braking method in an emergency situation, you should:

Explanation
The stab braking method for emergency stops involves fully applying the brakes until they lock up. The brakes are then released until the wheels start rolling, then the process is repeated.

22. Some air brake systems use alcohol:

Explanation
Some air brake systems contain an alcohol evaporator. This device introduces alcohol into the braking system to inhibit the formation of ice.

23. When you press the brake pedal in a vehicle with S-cam brakes, air pressure pushes out the rod and moves the:

Explanation
When pressing the brake pedal in a vehicle with S-cam brakes, air will enter the brake chambers. The added air pressure will push out the rods and move slack adjusters, twisting the brake camshafts.

24. Truck tractors with air brakes that were built on or after March 1, 1997 are equipped with:

Explanation
Truck tractors with air brakes that were manufactured on or after March 1, 1997 are required to be equipped with Anti-Lock Braking Systems (ABS). ABS is required in any other type of vehicle with air brakes that was manufactured on or after March 1, 1998.

25. Most heavy-duty vehicles use:

Explanation
Most heavy-duty vehicles use dual air brake systems, in which there are two separate braking systems operated by a single set of controls. Each system operates the brakes on different axles.
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