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 four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the West Virginia Commercial Driver’s 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. Brake fading is caused when:

Brakes are not used often enough.

Brakes overheat.

Brakes are too cold.

Brakes are wet.

Using the brakes excessively will cause them to overheat, making them less effective. This is referred to as "fading."

20. How is water and compressor oil removed from the bottom of an air storage tank?

The water and oil are siphoned out of the tank.

A drain valve is opened to remove the water and oil from the tank.

The water and oil are removed automatically as the brakes are used.

A sponge is used to soak up the water and oil.

Water and compressor oil are removed from air storage tanks through a drain valve. The water and oil can damage the brakes if left to accumulate in the system. Manually operated tanks must be drained every day to remove this build-up.

21. An air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately ____ to come to a complete stop.

100 feet

250 feet

300 feet

450 feet

A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

22. In a vehicle with dual parking control valves, once air pressure is lost and the spring brakes come on:

You will be unable to move the vehicle.

A separate air tank can be used to release the spring brakes for a short period of time.

You can use the spring brakes to continue driving normally.

The air tanks will automatically refill to a safe air pressure level.

In a vehicle with dual parking control valves, there is a separate air tank that can be used to temporarily release the spring brakes if they have been activated due to low air pressure. Pushing in the proper control will release the spring brakes for a short period of time, allowing the driver to move the vehicle in an emergency.

23. During an applied leakage test, the maximum leakage rate for a double combination vehicle is:

10 psi in a minute.

8 psi in a minute.

6 psi in a minute.

4 psi in a minute.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.

24. A tank endorsement is:

Only required when transporting gases.

Only required when transporting liquids.

Required when transporting both liquids and gases.

Optional when transporting hazardous materials.

With some exceptions, you must have a tank endorsement to transport liquids or gases. This applies to both hazardous and non-hazardous substances.

25. Service brakes should:

Be tested once a month.

Only be tested by a trained mechanic.

Be tested before every trip.

Before driving, you should always verify that your service brakes are in good working order. Testing the brakes before a trip allows you to locate any problems before you need to brake while on the road.

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