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 Colorado 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:

While driving, spring brakes are generally held in place by:

Explanation
While driving, spring brakes are generally held in place by air pressure. If the air pressure gets low enough, the springs will activate the brakes.

If using air tanks with manually operated drains, how often should you drain the tanks?

Explanation
To prevent the build up of oil and water in a vehicle's air tanks, manually operated air tank drains should be used at the end of each day of driving.

Air tank drains:

Explanation
In an air brake system, the air storage tanks must be drained to remove accumulated water and compressor oil. Failing to do so can cause damage. Manually operated drains should be used at the end of each day of driving.

Emergency brakes:

Explanation
All trucks, truck tractors, and buses must be equipped with emergency brakes and parking brakes. These brakes must be held by mechanical force.

What color are ABS malfunction lamps?

Explanation
Vehicles with Anti-Lock Braking Systems (ABS) have yellow malfunction lamps.

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.
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