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. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Commonwealth of Pennsylvania Commercial Driver’s Manual. Questions come from chapters covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
Number of Question
Passing Score
7. Both systems in a dual air brake systems share:
Explanation
Both systems in a dual air brake system share a single air compressor. If the air compressor is damaged, neither system will be able to operate properly.
8. 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.
9. How is water and compressor oil removed from the bottom of an air storage tank?
Explanation
Water and compressor oil are removed from air storage tanks through a drain valve. The water and oil can damage the brakes if left to accumulate in the system. Manually operated tanks must be drained every day to remove this build-up.
10. When a brake pedal is pressed and the S-cam is turned, the S-cam:
Explanation
When a brake pedal is pressed and the S-cam is turned, the S-cam presses the brake shoes against the inside of the brake drum. This causes friction and will cause the vehicle to slow.
11. How many air storage tanks are used in an air brake system?
Explanation
Air storage tanks are used to hold compressed air. The number and size of air tanks in an air brake system varies among vehicles.
12. If the brake pads rub against the brake drums and create too much heat:
Explanation
