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 Wyoming Driver License Manual for Commercial and Heavy Vehicles. 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. The air compressor governor controls:

When the air compressor pumps air into the air storage tanks.

How fast air is pumped into the air storage tanks.

The temperature of air pumped into the air storage tanks.

The speed of the vehicle.

In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.

2. Before driving a vehicle with a dual air brake system, you must wait for the air compressor to build a minimum of ____ in both the primary and secondary systems.

25 psi

50 psi

75 psi

100 psi

Before driving a vehicle with a dual air brake system, you should wait for the air compressor to build up at least 100 psi in both the primary and secondary systems.

3. During an applied leakage test, the maximum leakage rate for a single vehicle with air brakes is:

3 psi in one minute.

6 psi in one minute.

8 psi in one minute.

4 psi in one minute.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.

4. The air entering air storage tanks may contain:

Water and compressor oil.

Frost.

Gravel.

Antifreeze.

The air that enters air storage tanks in an air brake system usually contains a certain amount of water and compressor oil. Because accumulations of these materials can damage the braking system, tanks are equipped with drains to allow their removal.

5. When the brake pedal is depressed, air brakes work:

Immediately.

After a short delay.

After about a minute.

Only if the green lever on the control panel is pushed down.

After the brake pedal is pushed down in a vehicle with air brakes, it takes a half-second or more for air to flow through the lines and make the brakes work. This contrasts with hydraulic brakes used in cars and light and medium trucks, which instantly begin working when the pedal is pushed.