Ontario Air Brake (Z) Practice Test 10

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 provides the force in a spring brake chamber?

   1. A hydraulic piston
   2. A rubber diaphragm and air
   3. An electric solenoid
   4. A large coil spring

2. How much notice must you give to cancel a practical test without a fee?

   1. No notice is needed
   2. At least 7 days
   3. At least 48 hours
   4. At least 2 hours

3. On a long-stroke chamber, what does the trapezoidal tag under the clamp bolt show?

   1. The brake adjustment limit
   2. The chamber's maximum stroke
   3. The chamber's air pressure rating
   4. The date of last adjustment

4. What is the usual colour code for trailer air couplers?

   1. Red for service, black for supply
   2. Yellow for supply, green for service
   3. Blue for supply, red for service
   4. Red for supply, blue for service

5. What does an alcohol evaporator do?

   1. Helps stop moisture from freezing
   2. Cleans oil off the brake linings
   3. Cools the compressor on hot days
   4. Lubricates the slack adjusters daily

6. What is the most common brake chamber size?

   1. Size 12
   2. Size 36
   3. Size 30
   4. Size 20

7. How do you find the governor's cut-out pressure?

   1. Note where the warning light comes on
   2. Note where the safety valve opens
   3. Note where the gauges stop climbing
   4. Note where the spring brakes apply

8. What is the recommended way to test automatic trailer spring brake application?

   1. Pull out the trailer supply valve
   2. Disconnect the line under pressure
   3. Pull the trailer hand valve
   4. Pump the pedal to zero air

9. Your gauge shows an unusual pressure reading. Who should confirm it?

   1. No one; dash gauges are exact
   2. A technician using an accurate gauge
   3. The next driver of the vehicle
   4. A DriveTest examiner

10. You use the hand valve and the brake pedal at the same time. What pressure reaches the trailer?

    1. Only the hand valve pressure
    2. The two added together
    3. The higher of the two
    4. The lower of the two

11. In a doubles or triples combination, what air drop per minute is the upper limit?

    1. 5 psi (35 kPa)
    2. 8 psi (55 kPa)
    3. 4 psi (28 kPa)
    4. 6 psi (41 kPa)

12. What happens to pushrod stroke as brake linings wear?

    1. It becomes zero
    2. It stays the same
    3. It decreases
    4. It increases

13. A standard (round-port) type 30 clamp chamber: past what applied stroke is the brake out of adjustment?

    1. 2-1/2 in. (64 mm)
    2. 1-3/4 in. (45 mm)
    3. 2 in. (51 mm)
    4. 1-3/8 in. (35 mm)

14. Air pressure drops below about 60 psi while driving. What does the control valve do?

    1. Locks the spring brakes in the released position
    2. Exhausts air so spring brakes apply
    3. Opens the supply tank safety valve
    4. Switches over to using the trailer's air

15. Should you expect ABS to shorten your stopping distance?

    1. Yes, by about half the distance
    2. Yes, when the trailer also has ABS
    3. No, it prevents lock, not distance
    4. Yes, but only on dry pavement

16. How do you supply air to a trailer with the trailer supply valve?

    1. Hold it for five seconds
    2. Push the knob in
    3. Turn it to the left
    4. Pull the knob out

17. What type of brake chamber do almost all commercial vehicles use?

    1. Welded-shell chambers
    2. Hydraulic wheel cylinders
    3. Clamp-type chambers
    4. Bolt-flange chambers

18. While draining tanks, you see a lot of water from the secondary tank. What should you do?

    1. Add more alcohol to the evaporator
    2. Drain the supply tank last
    3. Nothing; it is always wet
    4. Report it; that is not normal

19. What is brake fade?

    1. The delay as air travels to the wheels
    2. Weaker brakes as they heat up
    3. A slow leak from the supply tank
    4. Wear marks on the inside of the drum

20. What is the job of the tractor protection valve?

    1. Raise air pressure in the trailer
    2. Limit braking on the steering axle
    3. Prevent air loss from the towing vehicle
    4. Keep the trailer spring brakes released

21. Why are the primary and secondary tanks called dry tanks?

    1. They hold only alcohol vapour
    2. They are drained by the air dryer
    3. They gather less moisture
    4. They contain no air until braking

22. Air-loss test on a straight truck with brakes applied: what is the most pressure it may lose in one minute?

    1. 1 psi (7 kPa)
    2. 4 psi (28 kPa)
    3. 3 psi (21 kPa)
    4. 6 psi (41 kPa)

23. How often must pushrod stroke be inspected?

    1. Every 5,000 km
    2. At least weekly
    3. At least daily
    4. Only after a brake job

24. Why must compressor brackets and fasteners be kept secure?

    1. So it keeps supplying air reliably
    2. So the governor can cut out much sooner
    3. So the tanks always stay below 80 psi
    4. So the drain valves stay closed while driving

25. What does the trailer supply valve knob normally look like?

    1. Blue and round
    2. Red and eight-sided
    3. Yellow and four-sided
    4. Black and triangular