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. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Illinois Commercial Driver’s License Study Guide. Questions come from chapters 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, a leak in one system:

Always means there are leaks in both systems.

May not affect the other system.

Is not something to worry about.

Will also affect the other system.

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.

8. Test the low pressure warning signal:

Once a month.

Once a week.

Twice a week.

Before every trip.

It is essential that your low pressure warning light function properly. After allowing the system to charge, you can test the warning signal by rapidly applying and releasing the brake pedal. This will release air from the braking system and the warning signal should come on when pressure drops to a dangerous level.

9. When about to drive a vehicle with a dual brake system, a driver should:

Let the vehicle warm up to ensure the fuel reaches the engine.

Wait for air pressure to build in both the primary and secondary systems.

Begin driving just after the engine starts.

Pump the pedal about 20 times to build pressure, then begin driving.

Before driving a vehicle with a dual air brake system, allow time for the compressor to build up pressure to at least 100 psi in both systems.

10. 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.

11. If you’re driving and the ABS warning light comes on, it means:

The ABS is working properly.

The ABS has just been activated.

The ABS is not working properly.

The ABS needs to be activated.

Vehicles with Anti-Lock Braking Systems (ABS) have yellow malfunction lights to alert the driver if something is wrong with the braking system. If these lights activate, the driver may have lost ABS on one or more wheels.

12. When traveling down a steep downgrade:

The air brakes should be used.

Shift into a lower gear, then use brakes to supplement the braking effect of the engine.

The vehicle should be continually downshifted in the place of using the brakes.

The vehicle should be driven on the shoulder.

On a downgrade, the braking effect of the engine should be your primary method of controlling speed. Shift down to a lower gear before starting down the hill and save the brakes for additional slowing or stopping that may be required by road or traffic conditions.

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