Ontario Z Air Brake Endorsement Practice Test 2026: Test d’entraînement 3

1. Question 1 sur 20

   Which situation is most likely to cause severe brake fade?

   • AUsing the engine brake on a short hill with an empty trailer
   • BA long downhill run with a heavy load at too high a speed
   • CParking overnight in very cold weather with the spring brakes on
   • DDriving slowly on a flat road in town with many stops
   Voir la réponse

   Réponse: B. A long downhill run with a heavy load at too high a speed

   Long descents, overloading and too much speed can overheat the brakes so badly that you cannot stop.

2. Question 2 sur 20

   What helps reduce brake heat on long downgrades?

   • AShifting to neutral
   • BPumping the brake pedal quickly
   • CUsing an engine brake or retarder
   • DTurning off the air compressor
   Voir la réponse

   Réponse: C. Using an engine brake or retarder

   Engine brakes and retarders slow the vehicle without heating the service brakes.

3. Question 3 sur 20

   In a dual air brake system, what happens if one circuit fails?

   • AAll the brakes release at once and cannot be applied
   • BThe trailer uncouples automatically from the tractor
   • CThe other circuit should still be able to stop the vehicle
   • DThe engine shuts off and the vehicle coasts to a stop
   Voir la réponse

   Réponse: C. The other circuit should still be able to stop the vehicle

   Dual systems split air into primary and secondary circuits so one can still stop the vehicle if the other fails.

4. Question 4 sur 20

   In a dual air system, where does air go after the supply (wet) tank?

   • AInto the fuel tank to help push the fuel
   • BStraight to the exhaust, then out of the vehicle
   • CInto the primary and secondary (dry) tanks
   • DBack into the compressor to be pumped again
   Voir la réponse

   Réponse: C. Into the primary and secondary (dry) tanks

   Air from the supply tank is split into the primary and secondary dual-service tanks.

5. Question 5 sur 20

   What does the air dryer do?

   • ADries the tires after driving through rain
   • BRemoves moisture before air enters the supply tank
   • CMeasures the air pressure in each tank
   • DHeats the brake drums so they work in winter
   Voir la réponse

   Réponse: B. Removes moisture before air enters the supply tank

   The air dryer removes moisture before the air reaches the supply tank.

6. Question 6 sur 20

   What is an alcohol evaporator for?

   • ATo add alcohol vapour to the air and reduce freezing in the system
   • BTo test the driver's breath for alcohol before starting
   • CTo cool the engine on long, steep hills
   • DTo clean the windshield in freezing weather
   Voir la réponse

   Réponse: A. To add alcohol vapour to the air and reduce freezing in the system

   An alcohol evaporator puts alcohol vapour into the air to help stop moisture freezing in the lines and valves.

7. Question 7 sur 20

   Why is the supply tank called the wet tank?

   • AIt collects most of the moisture and oil from the compressed air
   • BIt is mounted under the fuel tank and gets wet in rain
   • CIt is filled with water on purpose to cool the air
   • DIt holds the windshield washer fluid for the cab
   Voir la réponse

   Réponse: A. It collects most of the moisture and oil from the compressed air

   The supply tank receives air first and collects most of the moisture and oil.

8. Question 8 sur 20

   What does the one-way check valve do?

   • AStops air from flowing back out of a tank
   • BLets air flow both ways freely
   • CReleases air when pressure is high
   • DApplies the parking brake
   Voir la réponse

   Réponse: A. Stops air from flowing back out of a tank

   A one-way check valve lets air into a tank but prevents it from flowing back out.

9. Question 9 sur 20

   What is the job of the tractor protection valve?

   • ATo keep the tractor's air if the trailer is disconnected or breaks away
   • BTo control the trailer's lights and turn signals
   • CTo measure the trailer's weight before you drive
   • DTo protect the tractor's paint from stones thrown by the trailer
   Voir la réponse

   Réponse: A. To keep the tractor's air if the trailer is disconnected or breaks away

   The tractor protection valve prevents air loss from the towing vehicle when no trailer is attached or the trailer lines fail.

10. Question 10 sur 20

    What does the trailer supply valve control knob usually look like?

    • AA yellow, diamond-shaped knob
    • BA red, eight-sided push-pull knob
    • CA blue, round knob
    • DA green toggle switch
    Voir la réponse

    Réponse: B. A red, eight-sided push-pull knob

    The trailer supply valve has a red, eight-sided push-pull knob.

11. Question 11 sur 20

    Gladhands connect the air lines between tractor and trailer. Which colour is the supply (emergency) line?

    • ARed
    • BBlack
    • CBlue
    • DGreen
    Voir la réponse

    Réponse: A. Red

    Red gladhands are for the supply (emergency) line and blue are for the service line.

12. Question 12 sur 20

    What do the brake chambers do?

    • ARemove water and oil from the compressed air
    • BTurn air pressure into force on the push rod
    • CStore extra air for the horn and the seats
    • DCool the brakes by blowing air on the drums
    Voir la réponse

    Réponse: B. Turn air pressure into force on the push rod

    Air enters the chamber and pushes a diaphragm, which moves the push rod.

13. Question 13 sur 20

    What is a slack adjuster?

    • AA lever that links the push rod to the brake camshaft
    • BA spring inside the chamber that holds the parking brake
    • CA gauge on the dashboard that shows brake wear
    • DA valve that lets out extra air when pressure is too high
    Voir la réponse

    Réponse: A. A lever that links the push rod to the brake camshaft

    The slack adjuster connects the push rod to the camshaft and increases the braking force.

14. Question 14 sur 20

    What are foundation brakes?

    • AThe brake parts at each wheel, such as drums and shoes
    • BThe concrete pads that trucks park on at terminals
    • CThe brakes on the trailer's landing gear legs
    • DThe engine brake that slows the vehicle on hills
    Voir la réponse

    Réponse: A. The brake parts at each wheel, such as drums and shoes

    Foundation brakes are the wheel-mounted parts, such as drums or rotors and shoes or pads, worked by the air system.

15. Question 15 sur 20

    What applies the spring brakes?

    • AThe driver's foot on the pedal
    • BA large spring, which air pressure holds back
    • CAir pressure pushing on the diaphragm
    • DHydraulic fluid
    Voir la réponse

    Réponse: B. A large spring, which air pressure holds back

    Spring brakes are applied by a strong spring and released by air pressure, so they apply when air is lost.

16. Question 16 sur 20

    What are the service brakes used for?

    • AParking overnight only
    • BEmergency stops only
    • CHolding the trailer while coupling only
    • DNormal stopping, applied with the brake pedal
    Voir la réponse

    Réponse: D. Normal stopping, applied with the brake pedal

    Service brakes are the brakes you use for normal stops, applied with the pedal.

17. Question 17 sur 20

    What does it mean if a spring brake chamber is caged?

    • AIt has been filled with oil to stop it from rusting
    • BIt is locked so no one can steal the brake parts
    • CIt has a metal cover to keep out snow and road salt
    • DIts spring is held back by a caging bolt, so it will not apply
    Voir la réponse

    Réponse: D. Its spring is held back by a caging bolt, so it will not apply

    A technician can cage the spring with a bolt, for example to move a vehicle in an emergency. The protruding bolt shows it is caged.

18. Question 18 sur 20

    Why should you never try to take apart a spring brake chamber?

    • AThe spring is under very high tension and can injure you
    • BOpening it voids the trailer's registration
    • CIt is full of hot oil that can burn your hands
    • DIt contains a sensor that records brake use
    Voir la réponse

    Réponse: A. The spring is under very high tension and can injure you

    The spring in the chamber is under very high tension. Never try to service or repair it.

19. Question 19 sur 20

    What is a DD3 chamber?

    • AA spring brake chamber with a caging bolt, used only on trailers
    • BA bus and coach brake chamber with three air connections and no large spring
    • CA diesel fuel filter used on buses and motor coaches
    • DA double-diaphragm gauge that shows two pressures at once
    Voir la réponse

    Réponse: B. A bus and coach brake chamber with three air connections and no large spring

    DD3 chambers are used on buses and coaches. They have three air connections and no large power spring.

20. Question 20 sur 20

    You find an air brake defect during your inspection. What does Ontario law say about driving the vehicle?

    • AIt is illegal to drive a defective vehicle, and you must report the defect
    • BYou may drive it if the load is light or the trailer is empty
    • CYou may drive it if you drive carefully and below 50 km/h
    • DYou may drive it for up to 7 days before getting it fixed
    Voir la réponse

    Réponse: A. It is illegal to drive a defective vehicle, and you must report the defect

    Drivers must report defects, and it is illegal to drive a defective vehicle.

Clavier : 1–4 pour répondre, Entrée pour la question suivante.