Ontario Air Brake (Z) Practice Test 7

All 25 questions in this test

Every question and its answer choices. The correct answers and explanations appear when you take the test above.

1. Why might spring brakes fail to hold a parked truck on a hill?

   1. The governor cut-in is set too high
   2. The air dryer is purging too often
   3. The brakes are out of adjustment
   4. The trailer supply valve is closed

2. In Method 1, how do you mark the pushrod?

   1. A wide strip of coloured tape
   2. A narrow, precise chalk line
   3. A large paint dab on the drum
   4. A deep scratch made with a file

3. When must wheel chocks be used during an air brake inspection?

   1. Only if the truck is carrying a load
   2. Only during the governor cut-out test
   3. When you leave the seat with brakes off
   4. Only when parked on gravel surfaces

4. What do engine brakes and retarders help you avoid?

   1. Pushrod measurement
   2. Compressor cut-in
   3. Low tire pressure
   4. Excessive brake temperature

5. Where is an air dryer located?

   1. Between the compressor and the supply tank
   2. Between the foot valve and brake chambers
   3. Inside the secondary tank
   4. On the trailer supply line

6. Which kind of brake system is used on almost all cars and light trucks?

   1. Air-over-hydraulic brakes
   2. Air brakes
   3. Spring brakes only
   4. Hydraulic brakes

7. Which book is the official study guide for the air brake knowledge test?

   1. The Official Bus Handbook
   2. The Official MTO Driver's Handbook
   3. The Official Air Brake Handbook
   4. The CVOR Safety Manual

8. The trailer service brakes fail. How can you apply the trailer spring brakes?

   1. Open the trailer drain valves
   2. Push the blue tractor knob
   3. Use the trailer hand valve
   4. Close the trailer supply valve

9. A driver holds an Ontario air brake adjustment certificate. Which brakes may they readjust?

   1. Those with automatic slack adjusters only
   2. Those with manual slack adjusters only
   3. Any brake on any vehicle
   4. Only trailer brakes

10. When do the trailer service brakes apply?

    1. Only when the tractor is parked
    2. Only when the hand valve is used
    3. Only below 60 psi
    4. Whenever the brake pedal is pressed

11. In an S-cam brake, what does the pushrod stroke move first?

    1. The return spring inside the drum
    2. The slack adjuster on the camshaft
    3. The anchor pin mounted in the spider
    4. The brake shoes directly at the drum

12. Which parts are inside a service brake chamber?

    1. A rotor, pads and a caliper
    2. A coil spring, a caging bolt and a piston
    3. A diaphragm, a pushrod and a return spring
    4. A camshaft, rollers and an anchor pin

13. On a wedge brake, which way do the brake chamber pushrods point?

    1. Outward, away from the wheel
    2. Forward along the slack adjuster
    3. Up toward the frame rail
    4. Inward, toward the shoes and drum

14. Why must you know the size and type of every brake chamber on your test vehicle?

    1. To set the governor cut-out pressure
    2. To find each adjustment limit
    3. To report them to your insurance company
    4. To order spare parts after the test

15. For the air-loss test, what is the engine and pedal condition?

    1. Engine at 900 rpm, pedal half down
    2. Engine off, pedal held fully applied
    3. Engine off, pedal pumped
    4. Engine idling, pedal released

16. The low-air warning comes on at 50 psi. Does the vehicle pass?

    1. No, 55 psi is the minimum
    2. Only if it switches off again at 60 psi
    3. Yes, as long as the buzzer is loud
    4. Yes, anything above 40 psi passes

17. On most vehicles, how do you release the spring brakes with the control valve?

    1. Turn the knob a quarter turn
    2. Push the knob in to supply air
    3. Pull the knob out to exhaust air
    4. Press the brake pedal three times

18. Why should you park on a level surface before inspecting air brakes?

    1. The gauges read wrongly on a slope
    2. The compressor needs level ground to run
    3. Some checks release the parking brakes
    4. The tanks drain faster on a slope

19. When should you inspect the air compressor?

    1. With the engine stopped
    2. While draining the tanks
    3. While the governor is cutting in
    4. With the engine at high idle

20. Which problem can moisture and oil sludge from the wet tank cause?

    1. Faster air build-up after each stop
    2. Shorter pushrod stroke at every wheel
    3. Damaged seals and sticking valves
    4. Higher cut-out pressure on the governor

21. How should a compressor drive belt feel under firm hand pressure?

    1. It should not move at all
    2. It should give slightly
    3. It should move several inches
    4. It should slip off the pulley

22. What makes sure air moves through an air brake system as fast as possible?

    1. Larger brake drums at each wheel
    2. Heavier return springs in each shoe
    3. Special valves in the system
    4. A second, faster compressor

23. Which wheels get air from the primary circuit?

    1. Always the trailer axles first
    2. Always the rear drive axles
    3. Always the front steering axle
    4. It depends on the manufacturer

24. Can the trailer hand valve be used to hold a parked combination?

    1. No, never for parking or emergencies
    2. Yes, but only for short stops
    3. Yes, as long as the engine stays running
    4. Only when parked on level ground

25. How long can the brake application delay be in an air brake system?

    1. Up to about two seconds
    2. Up to about one-half second
    3. Up to about five seconds
    4. There is no measurable delay