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 or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Arkansas Commercial Driver License 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. An air compressor governor will stop the compressor from pumping air once the air tanks have an air pressure level of:
Explanation
An air compressor governor will stop the compressor from pumping air once the air tanks are at an air pressure level of 125 psi. This air pressure level is referred to as the "cut-out" level.
20. Air tank drains:
Explanation
In an air brake system, the air storage tanks are equipped with drains to allow water and compressor oil to be removed. The water and oil can damage the brakes if left to accumulate in the system.
21. Before driving a vehicle with a dual air brake system, you must wait for the air compressor to build a minimum of ____ in both the primary and secondary systems.
Explanation
Before driving a vehicle with a dual air brake system, you should wait for the air compressor to build up at least 100 psi in both the primary and secondary systems.
22. Air brakes are:
Explanation
As long as the brakes are properly maintained, using air brakes is a safe and effective method of stopping large, heavy vehicles.
23. A tank endorsement is:
Explanation
Subject to certain conditions, a tank endorsement is required to operate a tank vehicle that is used to haul either liquids or gases.
24. 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.
25. If using air tanks with manually operated drains, how often should you drain the tanks?
Explanation
