MB Air Brake Test 4

Do you want to drive a truck in Manitoba? To be a commercial driver in this province, you need a licence that is specific to the type of truck you want to drive. As a truck driver, you are a critical part of the transportation industry. The power and size of large trucks are awe-inspiring. Even while you’re driving safely, the smallest mistake can cause serious damage. Before you can get your commercial driver’s licence, you must pass both a written and practical test. The written test (also known as the Manitoba commercial driver’s licence knowledge exam) has several multiple-choice questions. You must get at least an 80% to pass the knowledge examination. This 50-question practice test will help you to prepare for the Manitoba (MB) Air Brake written test required to get your commercial driver’s licence. As you answer the questions on this test, we recommend checking each question’s explanation to gain further insight into the rule behind it. All questions on this test are based on the 2025 MB commercial driver’s guide. Good luck and drive safely!

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MB Driver and Vehicle Services

Official Manitoba driver's manual (2025)

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Written by Andrei Zakhareuski Updated over a week ago

At Tests.ca, we understand the importance of reliable and accurate practice tests to help you prepare for your driver's knowledge exam. That's why we've developed a meticulous process to create and continually update our practice questions, ensuring they reflect the most current driving laws and regulations.

Here's an inside look at how we maintain the highest quality in our practice tests.

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We leverage feedback from our vast community of users to understand which topics are most frequently tested. This helps us focus on the areas that are most relevant and beneficial for your preparation.
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Our thorough quality control process ensures that you have access to practice tests that are as accurate and up-to-date as possible. We believe in the power of well-prepared drivers and are dedicated to providing you with the best study tools to help you succeed on your driver's knowledge exam.

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List of questions (classic view)

How often should the air tanks be drained?
On a tractor-trailer, if the supply and service lines to the trailer are cross-connected, what may happen?
How do you release DD3 safety actuator brakes?
When you're going to tow a trailer, how can you tell if the trailer's antilock braking system (ABS) is working?
Wedge brakes are
The purpose of the tractor protection valve is
To test the tractor protection valve, disconnect the trailer service line and
In a tractor-trailer, the connections between the tractor and the trailer include which of the following components?
The hand valve control ("spike") applies
Which brakes are more powerful, the spring brakes or the service brakes?
Which of the following is NOT a part of a truck's braking system?
A tractor-trailer's braking system supplies compressed air to which trailer brakes FIRST?
An S-cam is found in
When coupling a tractor to a trailer, how many air lines do you have to connect?
If there is a loss of air to the service brakes in a trailer with a spring brake priority system, how can you brake the trailer to a stop?
In a trailer with a spring brake priority system, compressed air is supplied to which brakes FIRST?
How many air lines must be connected to a DD3 safety actuator brake chamber?
The tractor protection valve closes to stop the flow of compressed air to
To uncouple your tractor from the trailer, how should you set the trailer air supply valve?
Which of the following is not a component of a wedge brake?
How often should you check brake chamber pushrod travel?
Which of the following is a part of a disc brake?
In an air braking system, which of the following is not commonly part of a disc brake?
Which of the following are helpful in reducing heat in the air brake system?
Which of the following can affect pushrod stroke?
If you find a major defect in the air brake system, you should
How can you determine applied pushrod stroke?
Which is least likely to cause brake drums to overheat?
When must full braking capability be available?
In Canada, antilock braking systems (ABS) have been mandatory on all trucks and buses over 4,560 kg that have been manufactured since
Which of the following is the best way to inspect an air compressor?
When can you adjust automatic slack adjusters?
If the outer layer of an air line is damaged, but the inner tube is still OK, what should you do?
To make sure the air tanks are securely attached to your vehicle, you should
Before inspecting your air brakes, you should
Your vehicle passes the tug test of the parking brakes if
If the brake chambers on opposite sides of an axle are of different sizes, the result may be
To check the brake chambers for leaks, you should
in a drum brake, the brake lining is fastened to
Compared with the service tanks, how much moisture should the supply tank discharge?
What is the appropriate action to take when brakes overheat due to overuse or improper adjustment?
Which of the following is incorrect about what could happen when the brake builds up too much heat?
What is the working mechanism of an air compressor?
What does MELT stand for when you must show you have completed an approved MELT course?
How far ahead can you book your driving test appointment?
Why are air brake systems predominantly used on large commercial vehicles?
After meeting what criteria can a licence holder be authorized to operate vehicles equipped with air brakes as a learner?
Who should supervise a learner handling air brakes?
What is the main function of the air compressor in a vehicle's brake system?
Which component allows the air to move through the system as quickly as possible?