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 three answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Kentucky 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

19. What do air brakes use to make the brakes work?

Compressed air

Outside air

Non-compressed air

Many large CMVs are equipped with air brakes. An air braking system uses compressed air to operate.

20. Air tank drains:

Should not be used in cold weather.

Are helpful to remove water and oil from the air tanks.

Are used to move air to the brakes.

Compressed air in an air brake system usually has a certain amount of water and oil in it. This can harm the system if allowed to accumulate. Air tanks have drain valves to aid in removing water and oil from the compressed air.

21. Failing to drain air tanks could result in:

Water accumulations freezing and causing brake failure.

Squishy brakes.

Too much air collecting in the tanks.

In an air brake system, the air tanks must be periodically drained to remove accumulations of water and compressor oil. If water is not removed, it could freeze in cold weather and cause brake failure.

22. If the spring brakes are on, you should:

Not use the brake pedal.

Press the accelerator.

Move the steering wheel.

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.

23. When experiencing cold weather, be sure to check your vehicle's alcohol evaporator:

Every three hours.

Every day.

Every other week.

An alcohol evaporator can help prevent ice from building up in an air brake system. In cold weather, the evaporator should be checked and refilled every day.

24. You should ____ if the low pressure warning signal activates while you are driving.

Stop where you are and park

Exit the roadway as soon as safely possible

Continue driving normally

If the low pressure warning signal activates while you are driving, it is important that you safely exit the roadway as soon as possible and park your vehicle. If the air pressure gets too low, the brakes will no longer work well enough for you to stop safely.

25. If the low air pressure warning signal comes on, you should:

Continue driving, but have the brakes repaired within a week.

Pull over and inspect the brakes.

Phone a mechanic while driving.

If the low air pressure warning signal comes on while you are driving a vehicle with air brakes, you should immediately bring the vehicle to a safe stop while you are still able to control the brakes. Inspect and repair the brakes as soon as possible.

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