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Air Brake Test Ontario 2026 – Free Ontario Air Brake (Z) Questions

Original questions written from the official Ontario handbook, with an explanation for every answer.

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  • 263 questions
  • 11 practice tests
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Practice test 1 · Question 1Score 0/0

What does a slack adjuster do?

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All Ontario Air Brake (Z) practice tests

11 sets of 25 questions. Each set is fixed, so you can repeat it until you score 100%.

Exam facts

Key facts: Ontario Air Brake (Z) Endorsement Knowledge Test

Free Ontario air brake practice tests for the Z endorsement, written from the Official Air Brake Handbook that MTO updated on February 24, 2026. Every question is original, explains why the right answer is right, and names the handbook chapter it comes from. No sign-up, and your progress stays on your device.

The air brake test is mostly about numbers and procedures: cut-in and cut-out pressures, the 55 psi low-air warning, the 60 psi spring brake point, air-loss limits, build-up time and pushrod adjustment limits. This site drills each of those separately by topic, then mixes them in full practice tests and a timed-free mock exam.

What the test covers

Topics and question bank

Every question is tagged to one topic from the official handbook. Pick a topic to drill just that area.

Try a few

Sample Ontario Air Brake (Z) questions

Tap a question to see the answer. The full interactive test is at the top of the page.
  1. 1What does a slack adjuster do?
    • A. Measures the pushrod stroke for you
    • B. Controls when the compressor cuts in
    • C. Drains moisture from the brake chamber
    • D. Acts as a lever on the camshaft

    Slack adjusters are levers that multiply the force of the brake chambers; their effective length is critical.

  2. 2What are the metal trailer air line couplers commonly called?
    • A. Glad valves
    • B. Kingpins
    • C. Gladhands
    • D. Clevis pins

    Two pairs of metal couplers called gladhands connect the supply and service lines. Each has a flexible seal that must be kept clean.

  3. 3When can you book the Z practical test?
    • A. Only after one year of driving
    • B. Before writing the knowledge test
    • C. After passing the knowledge test
    • D. Only with a Class A licence

    After your knowledge test at a DriveTest centre, you can book a practical test appointment.

  4. 4In Ontario, do you need a Z endorsement to drive a truck with air-over-hydraulic brakes?
    • A. No, only full air brakes need it
    • B. Yes, it is required
    • C. Only if the truck is over 11,000 kg
    • D. Only when towing a trailer

    Air-over-hydraulic systems combine compressed air with hydraulic brakes, and Ontario requires a Z endorsement to drive them.

  5. 5What happens when you press the brake pedal harder?
    • A. The spring brakes apply instead
    • B. Higher air pressure reaches the brakes
    • C. The compressor cuts out sooner
    • D. Air is released from the chambers

    Pressing harder opens the valve at the pedal further, sending higher pressure to the service brakes and increasing braking force.

  6. 6You will test in an air-braked dump truck with no trailer system. Which version applies?
    • A. A road test only
    • B. Version 1
    • C. Version 2
    • D. Either, at your choice

    If you do not have a tractor-trailer air brake system, you can take Version 2 of the practical test.

  7. 7What is the lowest actual cut-in pressure allowed?
    • A. 100 psi (690 kPa)
    • B. 55 psi (380 kPa)
    • C. 60 psi (414 kPa)
    • D. 80 psi (552 kPa)

    Actual cut-in must never be below 552 kPa (80 psi). 55 and 60 psi relate to the low-air warning and spring brakes.

  8. 8An air line was repaired with a fitting not approved for air brakes. What is it?
    • A. Acceptable for one trip only
    • B. Acceptable if it does not leak
    • C. Acceptable on trailer lines only
    • D. A defect; it is not allowed

    Air brake systems require fittings designed and approved for that use. Improper fittings or repairs are prohibited and are a defect.

  9. 9What does a pushrod stroke indicator show?
    • A. The date of the last brake inspection
    • B. Stroke is past the limit
    • C. How much brake lining is left
    • D. The chamber's current air pressure

    Pushrods are often marked with an indicator that becomes visible when stroke exceeds the limit. They must be properly installed and drivers trained to use them.

  10. 10To test the low-air warning, what pressure should you start above?
    • A. 145 psi (1000 kPa)
    • B. 60 psi (414 kPa)
    • C. 90 psi (621 kPa)
    • D. 55 psi (380 kPa)

    Begin with pressure above 621 kPa (90 psi). If pressure is too low, the warning comes on as soon as the key is turned on.

About the test

About the Ontario Air Brake (Z) Endorsement Knowledge Test

In Ontario you need a Z endorsement on your driver's licence to drive any vehicle equipped with air brakes, including trucks with air-over-hydraulic brakes. A vehicle that only uses air for its parking brake, such as some school buses, does not need one. The endorsement is added to a licence class such as A, D or G; it is not a licence class of its own.

There are two ways to earn it. You can take an air brake endorsement course from a fleet owner, a community college or a safety organization, then take your referral envelope to a DriveTest centre within six months. Or you can take the tests at DriveTest yourself: a written knowledge test first, then a practical test on an air-braked vehicle. Holders of B, C, D, E, F or G licences who choose the course route must take it through a fleet owner.

Neither ontario.ca nor DriveTest publishes how many questions are on the air brake knowledge test. DriveTest does say that its knowledge tests are multiple choice, not timed, marked on the spot, and that you need a total score of at least 80 percent to pass. Our mock exam uses 25 questions and a pass mark of 20 (80 percent) as a practice standard, not as the official format.

The practical test comes in two versions: Version 1 for vehicles with a tractor-trailer air brake system and Version 2 for other air-braked vehicles. You will be asked to inspect components, run the functional tests (low-air warning, build-up time, governor, air loss, tractor protection valve, trailer and spring brakes, drain valves) and measure applied pushrod stroke. Several of our topics follow that checklist so the written practice also prepares you for the practical.

Since September 1, 2023, drivers renewing a licence that carries a Z endorsement complete an online air brake learning module instead of rewriting the air brake knowledge test. The first-time knowledge test is still required, which is what this practice site is for.

Study plan

How to prepare

  1. 1Read the Official Air Brake Handbook once from start to finish. It is free on ontario.ca and every question here cites a chapter of it.
  2. 2Make a one-page list of the numbers: cut-out 20 to 25 psi above cut-in, cut-in never below 80 psi, cut-out never above 145 psi, safety valve about 150 psi, low-air warning at or above 55 psi, spring brakes apply around 60 psi, trailer supply valve closes between 20 and 45 psi.
  3. 3Learn the air-loss limits as a set: 3 psi per minute for a straight truck, tractor or bus, 4 psi for a tractor and trailer, and 6 psi for a tractor with two or more trailers.
  4. 4Practise the knobs and colours: yellow four-sided spring brake knob, red eight-sided trailer supply knob, round blue tractor parking knob, red supply gladhand and blue service gladhand.
  5. 5Take one practice test per topic, then reread the cited chapter for every question you miss. The explanations name the exact condition the answer depends on.
  6. 6Memorize the common adjustment limits: 2 inches for a standard type 30 chamber, 2-1/2 inches for a long-stroke type 30 with square ports, 1-3/4 inches for standard types 16, 20 and 24.
  7. 7When you score 22 or more out of 25 on two different mock exams in a row, you are ready to book the knowledge test.
  8. 8Before the practical test, gather the required items: wheel chocks, a watch with a second hand, a way to hold the pedal down, a pushrod marker, a stroke gauge and eye protection.

FAQ

Ontario Air Brake (Z) test questions people ask

How many questions are on the Ontario air brake test?

MTO and DriveTest do not publish the number of questions on the air brake (Z) knowledge test. Our mock exam uses 25 questions as a practice standard so you can time yourself and track progress, but treat that number as ours, not the official format.

What is the passing score for the Z endorsement test?

DriveTest states that its knowledge tests require a total score of at least 80 percent. Our mock exam asks for 20 out of 25, which is 80 percent. The test is not timed.

How much does the air brake test cost in Ontario?

DriveTest's fee list shows an air brake endorsement package of $66.00, which covers the knowledge test ($16.00) and the practical test ($50.00). Fees are set by the province and can change, so confirm on drivetest.ca before you go.

Do I need a Z endorsement for air-over-hydraulic brakes?

Yes. Ontario requires a Z endorsement for vehicles with air-over-hydraulic brakes. You do not need one for a vehicle that uses air only for its parking brake and hydraulic brakes for everything else.

Is there an air brake test PDF?

The Official Air Brake Handbook is free to read online at ontario.ca. We also have a printable questions-and-answers page that you can print or save as a PDF from your browser, with the answer key on a separate page.

Do I still have to write the air brake test when I renew?

No. Since September 1, 2023, renewal of a Z endorsement uses an online air brake learning module instead of the knowledge test. From age 80 the module and a practical test are needed every year.

Are these the real air brake test questions?

No. Real test questions are not public. Every question here is written by us from the Official Air Brake Handbook and cites the chapter it comes from.

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