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

1. Applying the brake pedal causes air pressure to activate an electric switch and:

Turn off the brake lights.

Turn on the low pressure warning light.

Turn on the brake lights.

Turn off the low pressure warning light.

In a vehicle with air brakes, the brake lights are activated when the brake pedal is pushed and air pressure moves an electric switch. With the application of air pressure, the switch will then turn on the brake lights.

2. You should ____ if the low pressure warning signal activates while you are driving.

Stop where you are and park

Exit the roadway as soon as safely possible

Continue driving normally

If the low pressure warning signal activates while you are driving, it is important that you safely exit the roadway as soon as possible and park your vehicle. If the air pressure gets too low, the brakes will no longer work well enough for you to stop safely.

3. The air pressure in a dual air brake system should build from 85 to 100 psi within:

Two minutes.

15 seconds.

10 minutes.

45 seconds.

When inspecting a vehicle with a dual air brake system, you should wait for air pressure to build from 85 to 100 psi in both the primary and secondary systems. This should take about 45 seconds.

4. When traveling down a steep downgrade, the best way to use your brakes is to:

Ride the brakes all the way down the hill.

Apply the brakes for a few seconds, then release the brakes for a few seconds. Continue to repeat these steps as you travel down the hill.

Apply the brakes only near the bottom of the downgrade.

Apply consistent pressure to the brake pedal all the way down the hill.

On a long or steep downgrade, brakes should only be used to supplement the braking effect of the engine. Apply the brakes just enough to feel a definite slowing down, then release them once you are about 5 mph below your target "safe" speed. Once your vehicle reaches its safe speed again, repeat this process.

5. Brakes out of adjustment will:

Work properly.

Cause some of the brakes to overwork and malfunction.

Allow better acceleration.

Brakes out of adjustment will fade before those that are properly adjusted. Brake adjustment must be checked frequently to help prevent brake issues.

6. What kind of force do emergency brakes use?

Air pressure

Mechanical

Heavy

Air brakes are really three different braking systems: the service brake, the parking brake, and the emergency brake. Emergency and parking brakes are applied with mechanical force.

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