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 Hawaii 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. Which of the following is not part of a vehicle’s air brake system?

Air gauges

Low pressure warning device

Air filter

Components of an air brake system include an air compressor, an air compressor governor, air storage tanks, air tank drains, an alcohol evaporator, a safety valve, a brake pedal, foundation brakes, supply pressure gauges, an application pressure gauge, a low air pressure warning signal, a stop light switch, a front brake limiting valve (on some older vehicles), spring brakes, and parking brake controls.

2. In a vehicle with dual air brakes, a leak in one system ____ the second system.

Will always affect

May not affect

Is caused by

A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.

3. 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.

4. What should happen before the air pressure in an air brake system tank falls below 55 psi?

The warning light should activate.

The vehicle will be unable to shift out of gear.

The front lights should flash.

The low air pressure warning signal must activate before the air supply pressure drops below 55 psi in the air tank. If the warning signal does not turn on when being tested during an inspection, the vehicle is not safe to drive.

5. The parking brake in a newer vehicle is applied by:

Moving a lever to the right.

Pushing a yellow, diamond-shaped knob.

Pulling a yellow, diamond-shaped knob.

In newer vehicles with air brakes, the parking brake is controlled by a yellow, diamond-shaped knob. The driver should pull the knob outward to apply the parking brakes and push the knob inward to release them.

6. 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.

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