Ontario Air Brake (Z) Practice Test 2026
Practise for the Ontario Z air brake endorsement with 100+ questions based on the Official Air Brake Handbook: air pressures, brake adjustment, pre-trip checks and safe operation.
Practice tests
About the Z air brake endorsement
The Z endorsement is needed to drive any vehicle with air brakes in Ontario. Added to a licence it becomes AZ, DZ, BZ, CZ and so on.
Key numbers from the Air Brake Handbook
- Normal system pressure range: around 690 to 828 kPa (100 to 120 psi).
- Cut-in pressure must never be lower than 552 kPa (80 psi); cut-out never higher than 1000 kPa (145 psi).
- The low-air warning must activate before pressure drops to 380 kPa (55 psi).
- Spring brakes apply automatically when pressure drops below about 414 kPa (60 psi).
- Pressure must build from 587 to 690 kPa (85 to 100 psi) within 2 minutes.
Official sources: Official Air Brake Handbook ↗
Frequently asked questions
What is the normal air brake pressure range?
The Official Air Brake Handbook gives the normal range as around 690 to 828 kPa (100 to 120 psi). Actual pressure must never be below 552 kPa (80 psi) or above 1000 kPa (145 psi).
When must the low air warning device activate?
Before pressure in either tank falls to 380 kPa (55 psi). Most devices activate at around 414 kPa (60 psi).
What is the allowed air loss rate?
With brakes applied: 21 kPa (3 psi) per minute for a single vehicle, 28 kPa (4 psi) with one trailer, and 41 kPa (6 psi) with two or more trailers.