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 or four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Arkansas 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. To stop a vehicle using air brakes:

The brake pedal should be pressed.

The brake pedal should be lifted.

The brake knob should be pulled out.

The brake knob should be pushed in.

To stop normally in a vehicle with air brakes, press down the brake pedal.

20. Manual air tank drains should be:

Opened to drain the tanks after each day.

Left open while driving.

Sealed with glue.

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. Manually operated air tank drains must be opened daily to remove this build-up.

21. While driving, spring brakes are generally held in place by:

Air pressure.

Chocks.

Foundation brakes.

Sturdy ties.

While driving, spring brakes are generally held in place by air pressure. If the air pressure gets low enough, the springs will activate the brakes.

22. A slack adjuster should move no more than ____ from where it is attached to the push rod.

Two inches

Five inches

One inch

Before a trip, you should check each slack adjuster after parking, setting wheel chocks, and disengaging the parking brake. Pull the slack adjusters to make sure that they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

23. When inspecting your brakes, a slack adjuster should move ____ from where it is attached to the push rod.

At least three inches

More than two inches

Up to five inches

No more than one inch

Check each slack adjuster after setting wheel chocks and disengaging the parking brake. Pull the slack adjusters to make sure they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

24. To confirm that a trailer has ABS, you can:

Look under the trailer for wheel speed sensors coming from the back of the brakes.

Look under the hood for the ABS sticker.

Look at the tires.

Remove a tire and look for the ABS sensor on the axle.

If you are unsure if a trailer is equipped with an Anti-Lock Braking System (ABS), look under the vehicle for the electronic control unit and wheel speed sensor wires coming from the back of the brakes.

25. You must have an air brake endorsement:

To use a vehicle with air brakes.

To drive any truck with a trailer.

To transport hazardous materials.

You must take an air brakes knowledge test to become licensed to operate a vehicle that is equipped with air brakes, including an air over hydraulic braking system.

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