Getting ready for your Q endorsement, or keeping your air brake knowledge sharp? Try these 29 free practice questions. Choose an answer for each one, then check your score. Every question shows a short explanation, so you learn as you go. No sign-up needed.
These are original practice questions written by Training Compliance Canada. They aren’t the official test questions. Pressure values follow Alberta’s Air Brake Manual and air brake practical test.
Which component makes the compressed air in an air brake system?
The engine-driven compressor makes the air. The governor only controls when it pumps.
What does the governor do when system pressure reaches cut-out?
At cut-out, the governor unloads the compressor. When pressure falls to cut-in, it puts the compressor back to work.
In Alberta's air brake check, cut-in pressure must be how far below cut-out pressure?
Cut-in must be 20 to 25 psi (138 to 172 kPa) below cut-out.
In Alberta's air brake check, governor cut-out must be between:
Cut-out must be between 120 and 135 psi (828 to 931 kPa).
With the engine at a fast idle, how quickly must air pressure build from 50 to 90 psi?
Pressure must build from 50 to 90 psi (345 to 621 kPa) within 3 minutes. Most trucks do it in about a minute to a minute and a half.
At about what pressure is the safety valve usually set to open?
The safety valve is usually set at about 150 psi (1,034 kPa) and protects the system from too much pressure.
What does a one-way check valve do?
A one-way check valve keeps air in the reservoir if pressure is lost upstream.
Why should air reservoirs be drained every day the vehicle is used?
Moisture and oil collect in the reservoirs. Water can freeze in lines and valves and stop the brakes from working properly.
What's the right way to drain a reservoir?
Opening the drain fully and letting all the air escape pushes the water out with it.
The low air pressure warning must come on at or before:
The warning, a buzzer and a light, must activate at or before 60 psi (414 kPa).
Spring brakes apply automatically when system pressure drops to somewhere between:
The park control knob pops out and the spring brakes apply between about 45 and 20 psi (311 to 138 kPa).
During the applied leakage test, you hold a full brake application for 2 minutes. What's the most a power unit with no trailer may lose?
The limit is 4 psi (28 kPa) for a power unit, plus 2 psi (14 kPa) for each trailer, after the system stabilizes.
What holds the spring brakes off while you drive?
Strong springs apply the brakes and air pressure holds them off. Lose the air and the springs apply the brakes.
Why must you never take apart a spring brake chamber?
The spring is extremely powerful. Only a trained technician, using a caging bolt, works on spring brakes.
On most trucks, the yellow diamond-shaped knob on the dash controls the:
Pull the yellow knob out to apply the spring brakes. Push it in to release them once there's enough air.
On a tractor, the red eight-sided knob controls the:
Push the red knob in to supply air to the trailer. Pull it out to cut off the supply, which applies the trailer's spring brakes.
What is the tractor protection valve for?
It closes off the air going to the trailer so the tractor keeps its air, and the trailer's emergency brakes apply.
With the trailer air lines disconnected and pressure dropping, the trailer air supply valve (red knob) must pop out at:
The red knob must pop out at 40 to 60 psi (276 to 414 kPa) or higher, protecting the tractor's air.
On a combination vehicle, what does the service (control) line do?
The service line carries the brake signal. The supply (emergency) line charges the trailer reservoirs and holds off the trailer's spring brakes.
About how long is brake lag in a well-maintained air brake system?
Brake lag, the time air takes to travel through the system, is about four tenths of a second. At 100 km/h you travel about 11 m in that time.
What does a relay valve do?
A small signal from the foot valve opens the relay valve, which sends air straight from a nearby reservoir to the rear chambers.
What does a quick release valve do?
It exhausts air from the chambers close to the brakes, so they release faster.
What does the slack adjuster connect?
The slack adjuster is a lever between the pushrod and the S-cam shaft. It also takes up slack as the linings wear.
How do you measure pushrod stroke?
Compare the measured stroke with the adjustment limit for that chamber type and size.
A brake with an automatic slack adjuster is out of adjustment. What should you do?
Automatic slack adjusters shouldn't need routine manual adjustment. If one is out, something is wrong and it needs to be checked.
In a typical dual air system on a truck, the primary circuit usually operates the:
Primary usually runs the rear service brakes and secondary the front. If one fails, the other can still stop the vehicle.
What causes brake fade?
Long or constant braking overheats the drums and linings. Drums expand away from the linings and braking power drops.
What's the safest way to go down a long, steep grade?
Let the engine help, and brake firmly in short applications so the brakes cool between them.
The low air warning comes on while you're driving. What should you do?
Stop safely and find the cause. If pressure keeps dropping, the spring brakes can apply on their own.
Go further
Our online course explains every topic on this test, with interactive gauges, a pushrod stroke check and a certificate when you pass.
How the Q endorsement works in Alberta
If you drive a vehicle with air brakes in Alberta, you need a Q endorsement on your driver’s licence. Here’s the process, according to the Alberta government’s Air Brake Program page:
- Take an approved air brake course from a licensed driver training school. The classroom session is a minimum of 6.5 hours.
- Complete the practical training, then a one-on-one practical assessment of the air brake pre-trip inspection, done within a 15-minute time limit.
- Pass the knowledge test at a registry. It has 30 multiple-choice questions, and you need 25 correct to pass. When you pass, the registry agent adds the Q endorsement to your licence.
Check the Alberta government page for current requirements and exemptions before you book.
What the test covers
Expect questions on the parts of the system and what they do, governor cut-out and cut-in, reservoirs and draining, the low air warning, spring brakes, dual air systems, tractor and trailer connections, the tractor protection system, pushrod stroke and brake adjustment, brake lag, and safe braking on downgrades.
Want to understand it, not just memorize it?
Our Air Brakes: Q Endorsement Knowledge course covers all of it in seven short, interactive lessons, including a working pressure gauge and a pushrod stroke check. It’s built for drivers preparing for the Q endorsement and for employers who want a documented air brake refresher for their crews. It doesn’t replace the approved course you need for the endorsement.
Frequently asked questions
Is this the official Alberta air brake test?
No. These are original practice questions on the same topics. The official knowledge test is taken at a registry after you complete an approved course.
How many questions are on the Alberta air brake knowledge test?
30 multiple-choice questions. You need 25 correct to pass.
Can I get my Q endorsement online?
No. Alberta requires an approved course from a licensed driver training school, including classroom and practical training, plus a practical assessment and the knowledge test.
Do I need to know the numbers?
Yes. Know the key pressures, such as when the low air warning must come on and when spring brakes apply, and how to check them. These are the values used in Alberta’s air brake practical test:
- Low air warning: on by 60 psi (414 kPa)
- Trailer air supply valve (red knob): pops out at 40 to 60 psi (276 to 414 kPa) or higher
- Park control valve (yellow knob): pops out at 20 to 45 psi (138 to 311 kPa)
- Compressor build-up: 50 to 90 psi (345 to 621 kPa) within 3 minutes at a fast idle
- Governor cut-out: 120 to 135 psi (828 to 931 kPa)
- Governor cut-in: 20 to 25 psi (138 to 172 kPa) below cut-out
- Applied leakage: a full brake application held for 2 minutes may lose no more than 4 psi (28 kPa) for a power unit, plus 2 psi (14 kPa) per trailer