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 Wisconsin Commercial Driver’s 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

7. In a dual air brake system:

Each system has separate air tanks, hoses, and lines.

The systems share air tanks, but each has its own separate hoses and lines.

Each system uses the same lines and hoses.

One system is the main braking system and a second system is ready to be used if the first one fails.

A dual air brake system is made up of two separate air brake systems. The systems share a single set of brake controls, but each has its own air tanks, hoses, and lines.

8. 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.

9. When operating a vehicle with a dual air brake system, the driver should:

Let the vehicle warm up before driving to ensure that the fuel reaches the engine.

Let the air compressor build up a minimum of 100 psi pressure in the primary and secondary systems before driving.

Begin driving just after the vehicle starts.

Before driving a vehicle with a dual air brake system, allow time for the air compressor to build up a minimum of 100 psi pressure in both the primary and secondary systems. Watch the air pressure gauges to monitor the pressure levels.

10. Air tank drains:

Allow rain water to enter the tanks.

Are used to drain water and oil from the tanks.

Should never be opened.

Must remain open while driving.

In an air brake system, the air storage tanks are equipped with drains to allow water and compressor oil to be removed. The water and oil can damage the brakes if left to accumulate in the system.

11. During an applied leakage test, what is the maximum leakage rate that is safe for a single vehicle with air brakes?

10 psi in one minute

5 psi in one minute

3 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.

12. In a dual air brake system:

Air tanks are shared between both systems.

Each system has its own air tanks.

You must designate which system you are using.

There are two air brake systems in a dual air brake system. The systems share a set of brake controls, but each system has its own tanks, hoses, and lines.

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