Ontario Air Brake (Z): Service brakes and brake chambers

All 20 questions in this test

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

1. In a dual-circuit service brake system, what happens if one circuit fails?

   1. Wheels on the other circuit still brake
   2. The compressor feeds the failed side
   3. All service brakes stop working
   4. Only the trailer brakes still work

2. Why must brake linkage be readjusted at regular intervals?

   1. Diaphragms shrink in cold weather
   2. Air tanks lose capacity over time
   3. Governor settings drift each week
   4. Wear makes the stroke longer

3. 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

4. What happens if pushrod stroke goes beyond the chamber's capacity?

   1. No more brake force is produced
   2. Brake force doubles
   3. The chamber vents to the air
   4. The spring brakes release

5. Application pressure rises from 10 psi to 80 psi. What happens to pushrod stroke?

   1. It stays exactly the same
   2. It drops to zero
   3. It increases noticeably
   4. It gets noticeably shorter

6. Where is compressed air turned into the mechanical force that applies a brake?

   1. In the governor on the compressor
   2. In the brake chamber at the wheel
   3. In the supply (wet) tank
   4. In the foot valve under the pedal

7. What are the brakes used for normal stopping called?

   1. Spring brakes
   2. Emergency brakes
   3. Parking brakes
   4. Service brakes

8. To find the right adjustment limit for a chamber, what must you identify?

   1. The axle weight rating
   2. Its style, type and size
   3. The compressor model
   4. Its colour and age

9. What happens when you press the brake pedal harder?

   1. The spring brakes apply instead
   2. Higher air pressure reaches the brakes
   3. The compressor cuts out sooner
   4. Air is released from the chambers

10. What does a front wheel-limiting valve do?

    1. Reduces service brake force on the steering axle
    2. Limits how far the steering wheel turns
    3. Stops the front wheels from turning when parked
    4. Holds the front brakes on during a skid

11. What is pushrod stroke?

    1. How long the compressor takes to cut out
    2. How far the shoes travel on release
    3. Distance the pushrod moves out
    4. How far the pedal moves when pressed

12. 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

13. How does Ontario law treat a brake whose stroke is past the adjustment limit?

    1. As a minor issue to note weekly
    2. As acceptable on trailer axles
    3. As normal wear until the next annual
    4. As a defect needing prompt attention

14. 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

15. 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

16. Who may readjust manual or automatic slack adjusters, according to the handbook?

    1. Only certified people
    2. Any licensed Z driver
    3. The vehicle owner at any time
    4. Any DriveTest examiner

17. When you release the brake pedal, what returns the pushrod into the chamber?

    1. The spring inside the chamber
    2. The weight of the slack adjuster
    3. Air from the secondary tank
    4. The governor at cut-in

18. Can you rely on hose colours to identify air lines on every vehicle?

    1. Yes, but only on trailers
    2. No, older vehicles may not follow the code
    3. Yes, all vehicles use one colour code
    4. No, colours are never used

19. What links the brake chamber pushrod to the brake assembly?

    1. The slack adjuster
    2. A one-way check valve on the axle
    3. A flexible rubber gladhand
    4. A clamp-type collar on the drum

20. 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