Ontario Z Air Brake Endorsement Practice Test 2026：第2套练习测试

1. 第1题，共25题

   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)
   显示答案

   答案: D. 28 kPa (4 psi)

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

2. 第2题，共25题

   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)
   显示答案

   答案: D. 41 kPa (6 psi)

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

3. 第3题，共25题

   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)
   显示答案

   答案: 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. 第4题，共25题

   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
   显示答案

   答案: C. Apply

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

5. 第5题，共25题

   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
   显示答案

   答案: 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. 第6题，共25题

   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
   显示答案

   答案: 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. 第7题，共25题

   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
   显示答案

   答案: 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. 第8题，共25题

   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
   显示答案

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

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

9. 第9题，共25题

   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
   显示答案

   答案: A. It is not securely mounted

   Air tanks must be securely mounted.

10. 第10题，共25题

    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
    显示答案

    答案: A. A crack or break in the drum

    Inspect brake drums or rotors for cracks or breaks.

11. 第11题，共25题

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

    • AAt least daily
    • BOnly after a crash
    • COnce a month
    • DOnce a year
    显示答案

    答案: A. At least daily

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

12. 第12题，共25题

    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)
    显示答案

    答案: 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. 第13题，共25题

    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
    显示答案

    答案: 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. 第14题，共25题

    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)
    显示答案

    答案: C. 51 mm (2 inches)

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

15. 第15题，共25题

    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)
    显示答案

    答案: 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. 第16题，共25题

    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)
    显示答案

    答案: C. 45 mm (1-3/4 inches)

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

17. 第17题，共25题

    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
    显示答案

    答案: 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. 第18题，共25题

    Which brake chamber size is the most common?

    • AType 30
    • BType 12
    • CType 36
    • DType 6
    显示答案

    答案: A. Type 30

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

19. 第19题，共25题

    Who may adjust manual slack adjusters?

    • AOnly certified technicians
    • BAnyone with a wrench
    • CAny driver with a Z endorsement
    • DAny passenger
    显示答案

    答案: A. Only certified technicians

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

20. 第20题，共25题

    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
    显示答案

    答案: 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. 第21题，共25题

    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
    显示答案

    答案: 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. 第22题，共25题

    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
    显示答案

    答案: A. It doubles

    Doubling the weight doubles the stopping distance.

23. 第23题，共25题

    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
    显示答案

    答案: A. It becomes four times as long

    Doubling speed increases stopping distance four times.

24. 第24题，共25题

    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
    显示答案

    答案: C. Eight times longer

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

25. 第25题，共25题

    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
    显示答案

    答案: 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.

键盘：按1–4作答，按 Enter 进入下一题。