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 North Dakota Commercial Driver 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. In a dual air brake system, a leak in one system:
Explanation
A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.
14. 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.
15. Where is the safety relief valve usually located?
Explanation
An air brake system's safety relief valve is located in the tank that is first to receive air from the compressor.
16. What should happen if the air pressure in the air brake system tanks falls below 60 psi?
Explanation
On vehicles with air brakes, a low air pressure warning signal will come on if the pressure in the air tanks falls below 60 psi. On large buses, the signal may activate at 80 to 85 psi.
17. An Anti-Lock Braking System (ABS):
Explanation
Anti-Lock Braking Systems (ABS) are compatible with air braking systems. ABS helps maintain control of a vehicle and prevents the wheels from locking up during hard braking on slippery surfaces. ABS can still provide benefits even if is present on only one axle.
18. If a vehicle has air brakes, the air compressor drive belt should be checked before each drive. In what condition should the belt be?
Explanation
