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 four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Indiana 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. During a walk-around inspection, ensure there are no cracks on the brake drums that are more than ____ of the width of the friction area.

One half

One quarter

One third

One tenth

Before beginning a trip, it is important to check the brake drums during your walk-around inspection. It is unsafe to drive if any brake drum has a crack more than one half of the width of the friction area.

20. The parking brake should be:

Used whenever you park the vehicle.

Used while driving.

Set when driving in bad weather.

Used to stop the vehicle in normal driving.

The parking brake should be applied every time you park your vehicle.

21. The emergency brake system uses:

Only parts of the parking brake system.

Only parts of the service brake system.

Parts of both the parking and service brake systems.

Only parts unique to the emergency brake system.

In an air brake system, there are three different braking systems: a service brake system, a parking brake system, and an emergency brake system. The emergency brake system uses parts of both the parking and service brake systems.

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

Continue driving normally.

Activate your hazard lights and continue driving.

Call the local law enforcement agency.

Safely exit the roadway and stop.

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.

23. Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:

Air pressure falls below 45 psi.

Air pressure falls below 20 psi.

Driving downhill.

Driving uphill.

Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.

24. If the low pressure warning light comes on while you are driving:

Braking will only be possible if there is still enough air in the tanks.

You can apply the brakes 14 times before the air in the system runs out.

You should continue to drive normally and check the brake system when it is convenient.

You should stay at least 100 feet away from other vehicles.

When driving a vehicle with air brakes, if the low air pressure warning light comes on, it is important for you to stop and safely park your vehicle as soon as possible. There may be a leak in the system. Controlled braking will remain possible only as long as there is enough air left in the tanks.

25. If a vehicle has air brakes, the air compressor drive belt should be checked before each drive. In what condition should the belt be?

Loose

Tight

Cracked

Bumpy

When inspecting a vehicle with air brakes that has a belt-driven air compressor, you should check the condition and tightness of the belt. It should be in good condition.

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