Ontario Commercial Drivers License Air Brakes Practice Test 4

Commercial Driver HQ is a website focused on helping new commercial drivers in all provinces and territories in Canada.

Our FREE practice tests are designed to help you succeed when it comes time to write the real test.

Each license type has 5 tests to help you study and become familiar with the rules and regulations of commercial driving. The tests are not identical to the license test you will need to pass, but the questions are similar to what you will find on the real deal.

Compatible on desktop, mobile, and tablet, you can take these tests anywhere you have internet access.

Take the practice test!

Created by Commercial Driver HQ

Ontario Air Brakes Practice Test 4

A 20 question practice test to help prepare you for your air brakes knowledge test in Ontario

1 / 20

A warning system must alert the driver when the pressure drops below?

2 / 20

Cut out pressure level must never exceed __________.

3 / 20

Correct belt tension for an air compressor can be determined by

4 / 20

Activation of trailer spring brakes can be checked by?

5 / 20

Who can perform adjustments and maintenance on your air brake system?

6 / 20

Which of these vehicles would usually have an air brake system?

7 / 20

Which of these is not part of an air brake system?

8 / 20

Why are their two service tanks?

9 / 20

What can cause the air pressure in the air brake system to drop?

10 / 20

What is a "glad hand"?

11 / 20

When brakes become overheated they also become?

12 / 20

What function does the alcohol evaporator perform?

13 / 20

How long should it take for the air pressure to rise from 587kPa to 690 kPa after the pressure had fallen below 552 kPa?

14 / 20

Which colour represent the trailer supply line?

15 / 20

What is the most frequent reason a vehicle is removed from service?

16 / 20

When inspecting an air brake system, the person inspecting should wear?

17 / 20

What is an ABS system?

18 / 20

Where is the air pressure gauge for the air brake system?

19 / 20

What is not a factor in how well your air brake system works?

20 / 20

How do you engage the emergency / parking brake on most air brake systems?

Thanks for taking the practice test!

Enter your info to sign up for our mailing list or click "See Result" to move on.

Your score is

The average score is 88%


We do our best to keep the questions current and accurate. The testing centres may change the questions on the knowledge tests at any time. Always be prepared for surprises.

Many of the answers to the questions can be found in the driver hand books or learning materials your province provides.

DISCLAIMER: CDHQ is not affiliated with DriveTest or the MTO. These practice tests should not be considered official tests and you are not granted a license for completing them. Our tests are simply a practice tool to help prepare yourself for the real test.