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

13. If the spring brakes are on, you should:

Not use the brake pedal.

Press the accelerator.

Move the steering wheel.

Be especially careful because the brakes may fail.

You should not apply the brake pedal if the spring brakes are activated. The brakes could be damaged if they are subjected to the force of air pressure and the springs at the same time.

14. If your tractor is equipped with ABS but your trailer is not, the ABS:

Will not be effective.

Will still improve your steering control.

Will make jackknifing easier.

Will allow others to see when you brake.

In a tractor-trailer combination, if the tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the ABS will still improve the driver's steering control. The driver should keep an eye on the trailer and let up on the brakes if the trailer begins to swing out.

15. The most common type of foundation brake used is the:

S-cam drum brake.

C-cam drum brake.

G-cam disc brake.

P-cam disc brake.

The most common type of foundation brake is an s-cam drum brake.

16. During a static leakage test, the maximum leakage rate for a triple combination vehicle with air brakes is ____ in a minute.

3 psi

5 psi

7 psi

9 psi

When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 psi in one minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

17. What can happen if the air pressure gets too low in an air brake system?

The brakes may squeak.

The brakes may not work.

The brakes may be sluggish.

The brakes will be very sensitive.

Pressing and releasing the brake pedal unnecessarily can let air out faster than the compressor can replace it, reducing the available air pressure. If the air pressure in an air brake system gets too low, the brakes will no longer work.

18. A low air pressure warning signal should activate:

When tank pressure falls below 120 psi.

When tank pressure falls below 60 psi.

When tank pressure falls below 10 psi.

When tank pressure falls below 5 psi.

In an air brake system, a low air pressure warning signal must come on if air pressure in the tanks falls below 60 psi. This warning signal may come in the form of a light, a buzzer, or a wig wag.

Grade This Section

See the exact questions that will be on the 2024 Illinois DMV exam.

99.2% of people who use the cheat sheet pass the FIRST TIME

Click Here
Full Cheat Sheet Unlock Your Exclusive Cheat Sheet!