Instructions

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.. Read More

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 two, three or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Nebraska 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 25

Passing Score 20

13. What is often found in compressed air?

Water

Cardboard

Brake fluid

Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Tanks must be drained regularly to remove this build-up.

14. The air storage tanks:

Hold only enough air for one braking cycle.

Hold enough air for the brakes to be used several times if the compressor stops working.

Do not hold air unless there is an emergency.

The air storage tanks in an air brake system store compressed air to be used for braking. They hold enough air for the brakes to still be used several times if the compressor stops working.

15. An Anti-Lock Braking System (ABS):

Is not available for vehicles with air brakes.

Is not helpful in most driving situations.

Can help you maintain control when braking.

Anti-Lock Braking Systems (ABS) are compatible with air brakes and help a driver maintain control of their vehicle by preventing wheel lockup.

16. Air tank drains should:

Only be used by mechanics.

Only be used when it is wet outside.

Be used to drain the tanks completely.

In an air brake system, air tank drains are used to remove water and compressor oil from the air tanks. When operating a drain, be sure to drain the tank completely.

17. Foundation brakes are used:

Only on the front wheels of a vehicle.

Only on the rear wheels of a vehicle.

On each wheel of a vehicle.

Foundation brakes are used on each wheel of a CMV. The most common type of foundation brake is the s-cam drum brake.

18. An Anti-Lock Braking System (ABS):

Cannot be used with air brakes.

Should be used on dry pavement.

Can assist in maintaining control when braking.

Should only be used if all axles have ABS.

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.

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