Ontario Z Air Brake Endorsement: How to Get It and What to Study

You need a Z endorsement to drive any vehicle with air brakes in Ontario. This guide explains how to get it, what the knowledge and practical tests cover, and the numbers from the Official Air Brake Handbook you must know.

Who needs a Z endorsement

In Ontario, most large commercial vehicles have air brakes. A Z endorsement on your driver's licence is required to drive any motor vehicle with air brakes. This includes:

• Tractor-trailers (the full licence is called Class AZ)
• Straight trucks, buses, school buses and other vehicles with an air brake system
• Vehicles with air-over-hydraulic brakes

You do not need a Z endorsement to drive a vehicle that has only air parking brakes.

Only the full Class A licence covers full air brake systems on both tractors and trailers. Practise with our Class A / AZ and Class D / DZ tests.

Two ways to get your Z endorsement

Option 1: Take an air brake course

Air brake endorsement courses are offered by vehicle fleet owners, community colleges and safety organizations.

• If you have a Class A licence you want to upgrade, you can use any of the three types of course provider.
• If you have a B, C, D, E, F or G licence, you must take the course with a vehicle fleet owner.

After the course you get an envelope. Take it to a DriveTest centre within 6 months to get your endorsement.

Option 2: Take the tests at DriveTest

1. Study the Official Air Brake Handbook from the Ministry of Transportation.
2. Go to a DriveTest centre and pass the air brake knowledge test. There is a fee for the test.
3. Book the practical test through DriveTest (a fee also applies).
4. If you need to cancel or change the appointment, do it at least 48 hours before, or you will pay a cancellation fee.
5. Bring an air brake vehicle and the required equipment, and pass the practical test.

What the knowledge test covers

The knowledge test is based on the Official Air Brake Handbook. The handbook's chapters are:

• Braking systems and the air supply (compressor, governor, tanks, valves)
• Service brakes, spring (parking and emergency) brakes and trailer brakes
• Foundation brakes, braking while driving, and compliance
• Inspecting components, system operation and brake adjustment

Practise with our free air brake Z practice test before you go.

What the practical test covers

There are two versions of the practical test:

• Version 1 is for a commercial vehicle with a tractor-trailer air brake system.
• Version 2 is for vehicles without a tractor-trailer air brake system.

You inspect the air brake system and tell the examiner what you are checking at each step. All drivers must show how to measure applied pushrod stroke.

What to bring

• Wheel chocks or blocks
• A stopwatch or a watch with a second hand
• Knowledge of the size and type of all brake chambers on your test vehicle
• A way to hold the brake pedal in the applied position
• A way to mark the pushrod and a device to measure pushrod stroke (not needed for motor coaches)
• Protective eyewear (not needed for motor coaches)
• A chart of brake-adjustment limits (optional)

Key pressures to memorise

• Normal system pressure: about 690 to 828 kPa (100 to 120 psi).
• Limits: never lower than 552 kPa (80 psi) or higher than 1000 kPa (145 psi).
• Governor: cut-out is normally 138 to 173 kPa (20 to 25 psi) above cut-in. Cut-in must never be below 552 kPa (80 psi). Cut-out above 1000 kPa (145 psi) is a defect. The handbook's key points also list cut-out below 690 kPa (100 psi) as a defect.
• Safety valve: normally opens at about 1035 kPa (150 psi).
• Low-air warning: must come on at or above 380 kPa (55 psi). Most come on at 414 kPa (60 psi) or higher.
• Spring brakes: release at about 414 kPa (60 psi). Below that they apply automatically and the control valve knob pops out.
• Trailer supply valve: closes automatically between 138 and 311 kPa (20 and 45 psi).
• Trailer spring brakes: must apply automatically when trailer line pressure drops below 414 kPa (60 psi).

Key checks to memorise

1. Secure the vehicle. Park on level ground, apply the spring brakes and chock the wheels.
2. Low-air warning test. Start with at least 621 kPa (90 psi), key on. Press and release the brake pedal until the warning comes on. It fails if it does not activate at or above 380 kPa (55 psi).
3. Pressure build-up test. Start below 552 kPa (80 psi) with the trailer supply valve closed. Run the engine at 600 to 900 rpm. Time the rise from 587 to 690 kPa (85 to 100 psi). More than 2 minutes is a defect.
4. Governor test. Check the cut-out and cut-in pressures are within the limits above.
5. Air-loss rate test. Engine off, service brakes fully applied, watch for one minute. Maximum loss: 21 kPa (3 psi) per minute for a straight truck, tractor or bus; 28 kPa (4 psi) for a tractor and trailer; 41 kPa (6 psi) for a tractor and two or more trailers.
6. Tractor protection valve test. Trailer supply valve closed, service line disconnected, brakes applied: no air should exhaust from the service line.
7. Trailer spring brake test. Close the trailer supply valve. The trailer spring brakes must apply.
8. Spring brake hold test. With spring brakes applied, gently apply power in low gear. The vehicle may rock but must not move significantly.
9. Pushrod stroke. Check daily. Measure with 621 to 690 kPa (90 to 100 psi) in the tanks, engine off, service brakes fully applied and spring brakes released. If any stroke is over the limit for that chamber size and type, the brake is out of adjustment and the vehicle is defective.
10. Drain tanks. Drain the supply (wet) tank first. Report a lot of moisture in other tanks, any oil outside the supply tank, or a drain valve that does not work.

It is illegal to drive a defective vehicle.

Renewing your Z endorsement

Since September 1, 2023, an online air brake learning module has replaced the air brake knowledge test at renewal.

1. Complete the module online before you go to renew. You need your driver's licence to start it.
2. Download or print the Certificate of Completion.
3. Bring the certificate and your licence to a DriveTest centre or your Driver Certification Program organization.

You can also do the module in person at a DriveTest centre. Commercial licence holders (A to F) still take the vision test and the commercial class knowledge test in person. Under age 80, renewal is usually every 5 years. From age 80, you must do the learning module and the practical test every year.