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 Arizona 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. Brakes out of adjustment will:

Work properly.

Cause some of the brakes to overwork and malfunction.

Allow better acceleration.

Brakes out of adjustment will fade before those that are properly adjusted. Brake adjustment must be checked frequently to help prevent brake issues.

20. Friction in an S-cam brake is caused when the brake shoes and linings:

Press against the outside of the brake drum.

Press against the inside of the brake drum.

Push against each other.

Friction inside a brake drum is caused when the brake shoes and linings push against the inside of the drum. The friction in the drums will slow and stop the vehicle.

21. In a vehicle with dual parking control valves, a separate air tank can be used:

To make the air brakes work more effectively.

To temporarily release the spring brakes.

To charge the brakes on the rear trailer.

In a vehicle with dual parking control valves, there is a separate air tank that can be used to temporarily release the spring brakes if they have been activated due to low air pressure. Pushing in the proper control will release the spring brakes for a short period of time, allowing the driver to move the vehicle in an emergency.

22. 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.

23. Lights that indicate that anti-lock brakes are not working are:

Gray.

Blue.

Yellow.

Vehicles equipped with Anti-Lock Braking Systems (ABS) have yellow malfunction lights to indicate issues in the braking system.

24. During an applied leakage test, the maximum leakage rate for a double combination vehicle is ____ in a minute.

2 psi

4 psi

6 psi

It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.

25. Alcohol evaporators are:

Illegal.

Used to introduce alcohol into air brake systems.

Only allowed in the northern parts of the state.

Some air brake systems have alcohol evaporators, which introduce alcohol into the braking system to help prevent the formation of ice.

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