Ontario Air Brake (Z) Practice Test 9

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. What can happen if you load a truck beyond its rated capacity?

   1. Only fuel consumption goes up
   2. The brakes may not stop it safely
   3. The governor raises cut-out pressure
   4. The brakes adjust to the extra load

2. What is a good way to pinpoint an air leak in a hose?

   1. Pinch it shut with a pair of pliers
   2. Spray it with a little brake fluid
   3. Move it back and forth and listen
   4. Wrap it tightly with electrical tape

3. What is a slack adjuster's effective length?

   1. Wheel centre to the drum edge
   2. Chamber clamp to the pushrod tip
   3. Camshaft centre to the clevis pin
   4. Pushrod hole to the chamber vent

4. At about what pressure does a safety valve normally open?

   1. 120 psi (828 kPa)
   2. 100 psi (690 kPa)
   3. 200 psi (1380 kPa)
   4. 150 psi (1035 kPa)

5. During your inspection you see a caging bolt sticking out of a chamber. What should you do?

   1. Drive on; it means the brake is adjusted
   2. Remove the bolt yourself before leaving
   3. Note it for the next annual inspection
   4. Have the vehicle inspected and repaired now

6. Which parts are found on every air disc brake?

   1. Wedges and rollers
   2. Camshafts and anchor pins
   3. Drums and spiders
   4. Calipers and rotors

7. Why are air brakes used on large commercial vehicles?

   1. They send high forces over long distances simply
   2. They never need a daily inspection by law
   3. They work without any engine-driven compressor
   4. They stop faster than any hydraulic system

8. You find small holes on a brake chamber that were made by the manufacturer. What are they?

   1. Corrosion that must be reported
   2. Normal vent holes, not a defect
   3. Impact damage needing repair
   4. Signs the chamber was caged

9. A school bus has hydraulic service brakes and an air-operated parking brake. Is a Z endorsement needed?

   1. Yes, but only when the bus carries children
   2. No, air parking brakes alone don't need one
   3. Yes, any air component at all requires it
   4. Only if the air tank is larger than 50 litres

10. Which item is optional for the air brake practical test?

    1. Wheel chocks or blocks for the wheels
    2. A chart of brake adjustment limits
    3. A way to hold the brake pedal down
    4. A watch with a second hand for timing

11. What job does the return spring do inside an S-cam brake?

    1. Holds the brake applied when parked
    2. Pushes the pushrod out of the chamber
    3. Pulls shoes back, keeps rollers on cam
    4. Locks the camshaft during a hard stop

12. What is the cut-in pressure?

    1. Where the safety valve opens to vent air
    2. Where the spring brakes begin to apply
    3. Where the low-air warning device comes on
    4. Where the compressor resumes pumping

13. You hold a Class D licence. Where must you take a Z endorsement course?

    1. With a vehicle fleet owner
    2. With any safety organization
    3. At any community college
    4. At a DriveTest centre

14. What protects unused couplers on the towing vehicle from dirt and water?

    1. Plastic bags over the lines
    2. Dead-end or dummy couplers
    3. The trailer hand valve
    4. The tractor protection valve

15. How many air line connections join a trailer's brakes to the towing vehicle?

    1. Three: supply, service and parking
    2. One combined line
    3. Two: supply and service
    4. Four, one per trailer axle

16. What does ABS mainly help you keep during hard braking?

    1. Cooler brake drums
    2. A shorter stopping distance
    3. Steering control
    4. Higher air pressure

17. Your steer axle uses standard type 24 chambers. Which stroke limit applies to them?

    1. 1-3/4 in. (45 mm)
    2. 2 in. (51 mm)
    3. 1-3/8 in. (35 mm)
    4. 2-1/4 in. (57 mm)

18. How do you lower air pressure for the low-air warning test?

    1. Pull out the trailer supply valve
    2. Open the supply tank drain valve
    3. Disconnect the trailer service gladhand
    4. Press and release the pedal repeatedly

19. What forces the brake shoes against the drum in an S-cam brake?

    1. The S-shaped cam on the camshaft
    2. A caliper squeezing both of the shoes
    3. A wedge pushed in by the pushrod
    4. Hydraulic pistons inside each shoe

20. Using Method 2, how do you get the applied stroke?

    1. Divide the applied reading by two
    2. Add the two readings together
    3. Use only the released reading
    4. Measurement 2 minus measurement 1

21. What moves inside the service chamber when air enters it?

    1. A wedge between the shoes
    2. A one-way check valve
    3. A flexible rubber diaphragm
    4. A large coil spring

22. Your truck has an air dryer. Do you still need to drain the tanks?

    1. No, the dryer removes all moisture
    2. Yes, still drain them regularly
    3. Only the secondary tank needs it
    4. Only during the winter months

23. How are the service brakes and the parking/emergency brakes controlled?

    1. Only through the trailer hand valve
    2. Independently, as separate systems
    3. By the governor automatically
    4. By the same valve and lever

24. Before driving, what should you confirm about air pressure and the spring brakes?

    1. Pressure is below 60 psi to save fuel
    2. The service section is empty of air
    3. The springs are caged for the whole trip
    4. There is enough pressure to keep them off

25. How can you confirm the trailer spring brakes have applied?

    1. Gently apply power to see if it holds
    2. Read the date on the trailer's annual decal
    3. Check that the trailer ABS lamp is off
    4. Look for frost forming on the gladhands