Ontario Z Air Brake Endorsement Practice Test 2026: Practice test 2

1. Question 1 of 25

   In the air-loss test, what is the most pressure a tractor and one trailer may lose in one minute?

   • A41 kPa (6 psi)
   • B14 kPa (2 psi)
   • C55 kPa (8 psi)
   • D28 kPa (4 psi)
   Show answer

   Answer: D. 28 kPa (4 psi)

   A tractor and trailer may lose no more than 28 kPa (4 psi) per minute.

2. Question 2 of 25

   In the air-loss test, what is the most pressure a tractor with two or more trailers may lose in one minute?

   • A69 kPa (10 psi)
   • B21 kPa (3 psi)
   • C28 kPa (4 psi)
   • D41 kPa (6 psi)
   Show answer

   Answer: D. 41 kPa (6 psi)

   A tractor with two or more trailers may lose no more than 41 kPa (6 psi) per minute.

3. Question 3 of 25

   How do you know the tractor protection valve is defective during the test?

   • AThe low air warning comes on at 414 kPa (60 psi)
   • BAir exhausts from the trailer service line when you press the pedal
   • CThe trailer spring brakes apply when you close the supply valve
   • DThe governor cuts out at 828 kPa (120 psi)
   Show answer

   Answer: B. Air exhausts from the trailer service line when you press the pedal

   With the trailer supply closed, pressing the pedal should not send air out of the trailer service line.

4. Question 4 of 25

   When you close the trailer supply valve during the test, what should the trailer spring brakes do?

   • ARelease
   • BStay as they were
   • CApply
   • DLock the tractor's steering
   Show answer

   Answer: C. Apply

   Trailer spring brakes must apply when the trailer supply valve is closed. If they do not, the system is defective.

5. Question 5 of 25

   How do you test the spring (parking) brakes' holding ability?

   • AWith them applied, gently apply engine power and see if they hold
   • BDrain all the air tanks first, then try to roll the vehicle
   • CDrive at highway speed and pull the parking brake control
   • DRelease the spring brakes and push the pedal hard
   Show answer

   Answer: A. With them applied, gently apply engine power and see if they hold

   The spring brakes are defective if they do not hold the vehicle still when engine power is applied gently.

6. Question 6 of 25

   When draining the air tanks at the end of the pre-trip check, which tank do you drain first?

   • AThe primary tank
   • BThe secondary tank
   • CThe supply (wet) tank
   • DThe trailer tank
   Show answer

   Answer: C. The supply (wet) tank

   Drain the supply tank first, because it collects most of the water and oil, then check each drain valve.

7. Question 7 of 25

   Where should you do the mechanical part of the air brake inspection?

   • AIn a live traffic lane with your four-way flashers on
   • BOn a hill, so the brakes are under load while you check them
   • CAnywhere, with the engine running at high rpm
   • DOn level ground, away from traffic, with the engine off and wheels chocked
   Show answer

   Answer: D. On level ground, away from traffic, with the engine off and wheels chocked

   Park on level ground away from traffic, shut off the engine, apply the spring brakes and chock the wheels.

8. Question 8 of 25

   During the mechanical inspection, what do you check on the air compressor?

   • AThe tire pressure on the nearest wheel
   • BThe drive belt condition and tension, and the mounting
   • CThe fuel level and the oil in the fuel tank
   • DThe colour of the paint and the make of the compressor
   Show answer

   Answer: B. The drive belt condition and tension, and the mounting

   Check the compressor's belt, pulley, mounting, brackets and fasteners.

9. Question 9 of 25

   What makes an air tank defective in the mechanical inspection?

   • AIt is not securely mounted
   • BIt has some water in it before draining
   • CIt has a drain valve
   • DIt is painted
   Show answer

   Answer: A. It is not securely mounted

   Air tanks must be securely mounted.

10. Question 10 of 25

    Which brake drum condition is a defect?

    • AA crack or break in the drum
    • BA drum that is warm after driving
    • CDust on the outside of the drum
    • DA drum painted black
    Show answer

    Answer: A. A crack or break in the drum

    Inspect brake drums or rotors for cracks or breaks.

11. Question 11 of 25

    How often should you check the push rod stroke (brake adjustment)?

    • AAt least daily
    • BOnly after a crash
    • COnce a month
    • DOnce a year
    Show answer

    Answer: A. At least daily

    The handbook says brake adjustment should be checked at least daily.

12. Question 12 of 25

    When measuring applied push rod stroke, what pressure should the gauges show?

    • A380 to 414 kPa (55 to 60 psi)
    • B621 to 690 kPa (90 to 100 psi)
    • C1000 to 1035 kPa (145 to 150 psi)
    • D138 to 173 kPa (20 to 25 psi)
    Show answer

    Answer: B. 621 to 690 kPa (90 to 100 psi)

    Keep pressure at 621 to 690 kPa (90 to 100 psi) during the adjustment check, with the service brakes fully applied.

13. Question 13 of 25

    When is a brake considered out of adjustment?

    • AWhen applied push rod stroke is over the limit for that chamber
    • BWhen the push rod moves at all during a brake application
    • CWhen the drum feels warm after a short drive
    • DWhen the brake makes no noise as it applies
    Show answer

    Answer: A. When applied push rod stroke is over the limit for that chamber

    Any push rod stroke over the chamber's adjustment limit means the brake is defective.

14. Question 14 of 25

    What is the adjustment limit for a standard type 30 clamp-type brake chamber?

    • A76 mm (3 inches)
    • B32 mm (1-1/4 inches)
    • C51 mm (2 inches)
    • D64 mm (2-1/2 inches)
    Show answer

    Answer: C. 51 mm (2 inches)

    A standard type 30 chamber has an adjustment limit of 51 mm (2 inches).

15. Question 15 of 25

    What is the adjustment limit for a type 30 long-stroke chamber?

    • A64 mm (2-1/2 inches)
    • B89 mm (3-1/2 inches)
    • C45 mm (1-3/4 inches)
    • D51 mm (2 inches)
    Show answer

    Answer: A. 64 mm (2-1/2 inches)

    A type 30 long-stroke chamber (with square ports and stroke markings) has a 64 mm (2-1/2 inch) limit.

16. Question 16 of 25

    What is the adjustment limit for a standard type 24 chamber?

    • A35 mm (1-3/8 inches)
    • B57 mm (2-1/4 inches)
    • C45 mm (1-3/4 inches)
    • D64 mm (2-1/2 inches)
    Show answer

    Answer: C. 45 mm (1-3/4 inches)

    A standard type 24 chamber has a 45 mm (1-3/4 inch) limit.

17. Question 17 of 25

    What does the letter L stamped on a brake chamber cover mean?

    • AIt is a long-stroke chamber, with a longer adjustment limit
    • BIt is a left-side chamber
    • CIt is a low-pressure chamber
    • DIt is a light-duty chamber that is not allowed on trucks
    Show answer

    Answer: A. It is a long-stroke chamber, with a longer adjustment limit

    L marks a long-stroke design. Long-stroke chambers have longer adjustment limits than standard ones.

18. Question 18 of 25

    Which brake chamber size is the most common?

    • AType 30
    • BType 12
    • CType 36
    • DType 6
    Show answer

    Answer: A. Type 30

    The handbook notes that size 30 is the most common chamber.

19. Question 19 of 25

    Who may adjust manual slack adjusters?

    • AOnly certified technicians
    • BAnyone with a wrench
    • CAny driver with a Z endorsement
    • DAny passenger
    Show answer

    Answer: A. Only certified technicians

    Only certified technicians may adjust manual slack adjusters. Drivers should not try to repair automatic adjusters.

20. Question 20 of 25

    An automatic slack adjuster keeps needing to be re-adjusted. What does that mean?

    • AIt is working normally
    • BThe governor is set too high
    • CThere is a defect that must be repaired
    • DThe tires are under-inflated
    Show answer

    Answer: C. There is a defect that must be repaired

    Frequent re-adjustment of an automatic slack adjuster points to a defect in the brake.

21. Question 21 of 25

    About how long is the delay between pressing the brake pedal and the air brakes applying?

    • AThere is no delay with air brakes
    • BAbout 10 seconds
    • CUp to about half a second
    • DAbout 5 seconds
    Show answer

    Answer: C. Up to about half a second

    Air takes time to travel through the lines, so there is a split-second delay of up to about one-half second.

22. Question 22 of 25

    If you double the weight of your vehicle, what happens to the stopping distance?

    • AIt doubles
    • BIt halves
    • CIt stays the same
    • DIt increases eight times
    Show answer

    Answer: A. It doubles

    Doubling the weight doubles the stopping distance.

23. Question 23 of 25

    If you double your speed, what happens to the stopping distance?

    • AIt becomes four times as long
    • BIt becomes eight times as long
    • CIt doubles
    • DIt stays the same
    Show answer

    Answer: A. It becomes four times as long

    Doubling speed increases stopping distance four times.

24. Question 24 of 25

    If you double both your weight and your speed, how much longer is the stopping distance?

    • ATwo times longer
    • BFour times longer
    • CEight times longer
    • DSixteen times longer
    Show answer

    Answer: C. Eight times longer

    Doubling both weight and speed makes the stopping distance eight times longer.

25. Question 25 of 25

    What is brake fade?

    • AThe low air warning slowly fading out
    • BPaint wearing off the brake drums over time
    • COverheated brakes losing power, so you must push harder
    • DA slow leak in one of the air tanks
    Show answer

    Answer: C. Overheated brakes losing power, so you must push harder

    As brake parts overheat, they work less well and you must push harder on the pedal.

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