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

1. Foundation brakes are used:

Only at the front wheels.

Only at the rear wheels.

Only at the driver’s side wheels.

At each wheel.

Foundation brakes are used at each wheel. The most common type is the S-cam drum brake.

2. A tank endorsement is:

Only required when transporting gases.

Only required when transporting liquids.

Used when transporting both liquids and gases.

Optional when transporting hazardous materials.

In general, a tank endorsement is required to a drive tank vehicle used to transport liquids or gases. This applies to both hazardous and non-hazardous materials.

3. If you’re driving and the ABS warning light comes on, it means:

The ABS is working properly.

The ABS has just been activated.

The ABS is not working properly.

The ABS needs to be activated.

Vehicles with Anti-Lock Braking Systems (ABS) have yellow malfunction lights to alert the driver if something is wrong with the braking system. If these lights activate, the driver may have lost ABS on one or more wheels.

4. When you press the brake pedal in a vehicle with S-cam brakes, air pressure pushes out the rod and moves the:

Slack adjuster.

Axle.

Brake drum.

Alcohol evaporator.

When pressing the brake pedal in a vehicle with S-cam brakes, air will enter the brake chambers. The added air pressure will push out the rods and move slack adjusters, twisting the brake camshafts.

5. You should test the low pressure warning signal by:

Turning on the engine and applying the trailer hand brake.

Rapidly pressing and releasing the brake pedal.

Removing wheel chocks and disengaging the parking brake.

It is essential that your low pressure warning light functions properly. After allowing the system to charge, you can test the warning signal by rapidly applying and releasing the brake pedal. This will release air from the braking system and the warning signal should come on when pressure drops to a dangerous level.

6. The leakage rate for a single vehicle with air brakes should be no more than ____ in one minute during a static leakage test.

1 psi

2 psi

3 psi

When performing a static leakage test on a single vehicle with air brakes, the leakage rate should be no more than 2 psi in a minute. If the air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

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