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Air Brake Tests

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If your vehicle has an alcohol evaporator then every day during cold weather you should:

2 / 26

A straight truck or bus air brake system should not leak at the rate of more than __PSI per minute with the engine off and the brakes released

3 / 26

A modulated control valve allows you to control the:

4 / 26

If the air pressure did not reach the correct level during the allowed time, then

5 / 26

When is NOT a proper time to use a parking brake

6 / 26

In ideal conditions, a truck or a bus with an air brake going at 55 mph would require stopping distance of how many feet?

7 / 26

The air brake lag distance at 55 mph on dry pavement adds about______feet.

8 / 26

The proper use of the brake when going down a long steep grade after selection a proper gear is to brake until your speed is above ___ MPH below the posted speed for safety and release you brake

9 / 26

Air brake equipped trailers made before 1975

10 / 26

Why on long downhill grades, using a low gear and light steady pedal pressure instead of On-again, Off-again braking is recommended?

11 / 26

Modern air brake systems combine three different systems. They are the service, the parking, and the _ brakes

12 / 26

Modern air brake systems combine three different systems. They are the service, the parking, and the _ brakes

13 / 26

During normal driving, spring brakes are usually held back by:

14 / 26

It is not safe to drive a vehicle that has brake drums with cracks that are longer than ___ of the width of the friction area?

15 / 26

For emergency stab braking you should:

16 / 26

When brakes are applied the brake shoes will align to press against the:

17 / 26

If you do not have automatic tank drains, how often should you drain the oil and water from the bottom of compressed air storage tanks?

18 / 26

Your brakes are fading when:

19 / 26

Parking or emergency brakes of trucks and buses can be legally held on by _ pressure.

20 / 26

The most important thing to do when a low air pressure warning comes on is:

21 / 26

The brake system that applies and releases the brakes when the driver uses the brake pedal is the _____ brake system.

22 / 26

If you have a dual air brake system, it is considered fully charged at ___ PSI

23 / 26

The braking power of the spring brakes:

24 / 26

The supply pressure gauge shows how much pressure:

25 / 26

When should you push the brake pedal if the spring brakes are on?

26 / 26

It is accepted that too much heat caused by using your brakes too often can also cause:

Your score is

The average score is 73%


The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake test.

There are two parts to the air brake endorsement test – the written and the practical part. The written portion consists of 20 to 25 multiple-choice questions; this test is administered on a computer. The number of questions might vary depending on the state. Usually it is 20-25 questions. The pass mark for the written exam is 80%. Some of the important contents for the written exam includes:

  • Components of an air brake system and dual air brakes.
  • Inspection of the air brake system.
  • The safe use of air brakes.

For first-time CDL drivers, the knowledge exam is included in the skill test. Those adding an endorsement to their CDL will have to schedule their skill test through their local licensing office. The essence of the practical exam is to ensure that you can safely use air brakes.

To pass the practical test (skills test), you will have to demonstrate that you are good at:

  • Using appropriate pressure for different tasks
  • Building air pressure
  • Releasing brakes
  • Testing low air and,
  • Gauging air pressure

Take this CDL practice test now to prepare for the actual air brakes test.




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