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 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
1. Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:
Explanation
Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.
2. Why do large vehicles use air brakes?
Explanation
If used and maintained properly, air brakes are a safe and effective way to stop large, heavy vehicles.
3. A tank endorsement is:
Explanation
With some exceptions, you must have a tank endorsement to transport liquids or gases. This applies to both hazardous and non-hazardous substances.
4. Which part of the truck is the air compressor connected to?
Explanation
In an air brake system, the air compressor is connected to the engine through gears or a v-belt.
5. 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.
6. Some air brake systems introduce alcohol into the system to:
Explanation
