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 questions. Each question has three answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Vermont Commercial Driver’s 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
19. If the spring brakes are on, you should:
Explanation
Do not use the brake pedal when the spring brakes are on. This could damage the brakes by subjecting them to the combined forces of springs and air pressure.
20. Brake fade is a result of:
Explanation
If brakes are overused, they can become too hot. This overheating causes them to fade, making them less effective at slowing the vehicle.
21. What does an air compressor do in an air brake system?
Explanation
In an air brake system, the air compressor pumps air into the air storage tanks. The air compressor is controlled by the air compressor governor.
22. Air brakes use ____ to function.
Explanation
Air brakes function through the use of compressed air.
23. Using an Anti-Lock Braking System (ABS):
Explanation
An Anti-Lock Braking System (ABS) helps to provide additional control during hard braking, but does not necessarily shorten a vehicle's stopping distance.
24. If an air compressor is belt-driven, the belt should be routinely checked to ensure that it is:
Explanation
If your vehicle has air brakes, the air compressor drive belt should be checked before each drive. Check the tightness of the belt and verify that it is in good condition.
25. When an S-cam turns inside a brake drum, the S-cam:
Explanation
