Air Brakes

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This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written..

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 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.

Passing grade:

If your tractor is equipped with ABS but your trailer is not, the ABS:

Explanation
In a tractor-trailer combination, if the tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the ABS will still improve the driver's steering control. The driver should keep an eye on the trailer and let up on the brakes if the trailer begins to swing out.

A tank endorsement is:

Explanation
In general, a tank endorsement is required to a drive tank vehicle used to transport liquids or gases. This applies to both hazardous and non-hazardous materials.

If the air pressure warning light comes on, you should:

Explanation
If the air pressure warning light or buzzer comes on while you are driving, you should immediately stop and safely park the vehicle. This warning signal indicates that there is a problem in the air brake system that needs to be fixed.

What can happen if a parking brake is used in very wet weather when temperatures are below freezing?

Explanation
If you use the parking brakes when the weather is very wet and the temperature is below freezing, the brakes may become frozen, preventing the vehicle from moving.

A vehicle equipped with an Anti-Lock Braking System (ABS) uses a ____ light to warn that the system is not working properly.

Explanation
Anti-Lock Braking System (ABS) malfunction lamps are usually yellow. Even if the ABS isn't working properly, a driver will still have access to the vehicle's usual braking functions.

The application pressure gauge:

Explanation
In an air brake system, the application pressure gauge shows how much air pressure is being applied to the brakes. Not all vehicles with an air brake system have this gauge.
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