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 four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the New Hampshire CDL Driver’s Guide. 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
13. Which of the following is not a part of an air brake system?
Explanation
Air brakes consists of three separate braking systems: the service brake system, the parking brake system, and the emergency brake system.
14. Pressing and releasing a brake pedal unnecessarily can:
Explanation
In an air brake system, pressing and releasing the brake pedal unnecessarily can release air from the braking system faster than the compressor can replace it.
15. During an applied leakage test, the maximum leakage rate for a double combination vehicle is ____ in a minute.
Explanation
It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.
16. The ____ tells a driver how much pressure is in the air tanks.
Explanation
A vehicle that is equipped with air brakes must also be equipped with a supply pressure gauge. This gauge tells the driver how much air pressure is in each of the vehicle's air tanks.
17. The rods in S-cam brakes move the slack adjusters when air pressure is added to the brake chambers. This air pressure is added to the chambers when the driver:
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.
18. What do air brakes use to make the brakes work?
Explanation
