Our practice tests cover all the material that will be on the actual exam, including air brake system theory, air brake system components, and air brake inspection and maintenance procedures. By using our practice tests, you can identify any areas of weakness that you may have, and focus your studying efforts on those topics to reinforce your understanding.


Ontario Air Brake Test 04

1 / 30

You must never make an inspection of your brakes unless...?

2 / 30

The low air pressure warning device is defective if it fails to activate at a minimum level of...?

3 / 30

Air brake chamber leaks must be inspected for with...?

4 / 30

The amount of air loss from a system should be measured with the brake fully applied for how long?

5 / 30

When applying a test to the spring brakes, the test is only passed if...?

6 / 30

An air pressure buildup time test should be made with the engine idling between...?

7 / 30

The amount of moisture discharged from tanks other than the supply tank should be...?

8 / 30

The minimum pressure for compressor cut-in is...?

9 / 30

Air compressors should always be inspected with...?

10 / 30

The application of the automatic trailer spring brakes can be confirmed by...?

11 / 30

Spring brakes should be tested by applying the brakes and...?

12 / 30

The drive belt of an air compressor should give slightly under...?

13 / 30

A tractor hauling two or more trailers must not lose air pressure with the brakes fully applied at a rate of more than...?

14 / 30

Brake lining can be contaminated by...?

15 / 30

A straight truck, tractor or bus must not lose air pressure with the brakes fully applied at a rate of more than...?

16 / 30

The discovery of a small quantity of oil is only no cause for concern if it comes from...?

17 / 30

If air brake chambers on different sides of an axle are different sizes, this may cause...?

18 / 30

When testing the spring brakes on a towing vehicle and trailer, it is preferable to perform the test on...?

19 / 30

The outer cover of an air line has been damaged, but there is no leak to the inner tube. What action should you take?

20 / 30

When the air pressure has been reduced to below 552 kPa, it should then be able to rise from 587 kPa to 690 kPa within...?

21 / 30

A tractor protection valve should be tested by disconnecting the trailer service line and then...?

22 / 30

When checking air brake chambers, you should be looking out for...?

23 / 30

Brake lining is the friction material that is fastened to...?

24 / 30

The maximum allowable air loss for a tractor and trailer when the brakes are applied is...?

25 / 30

You should make sure that air tanks are securely attached to the vehicle by...?

26 / 30

If a vehicle has a foundation brake defect, the Ontario Highway Traffic Act specifies that it may not...?

27 / 30

You should begin a test of the low air pressure warning device with the pressure above...?

28 / 30

Actual cut-out pressure must never be higher than...?

29 / 30

The recommended way to test a trailer's automatic spring brakes is to...?

30 / 30

When checking a vehicle's brake drums, you should be looking out for...?

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Ontario Air Brake Test

Our free Ontario air brake test questions and answers will prepare you to pass Ontario’s official Air Brakes knowledge test. To begin your career in trucking, you must obtain your Ontario Class A or Class D Truck Driver’s Licence. The appropriate CDL endorsements you will need are based on the type of trucking career you plan to pursue. To obtain these endorsements, you must complete a written knowledge test successfully. Making sure you are adequately prepared for your written knowledge test will prevent you from wasting time and money. Taking practice CDL tests is the best way to get ready.

Passing your air brake test doesn’t have to be a stressful experience. Follow this important tip, and you should pass the test without a problem.

Eat and Sleep Well – Before the Ontario air brake test, ensure you eat and sleep well. A drop in blood sugar while taking the test can cause issues remembering what you have studied. You will also want to get a good night’s rest before test day. Being tired will significantly reduce alertness and hinder your ability to recall important facts when taking the test.