Chapter 10a: Inspecting Air Brake System Operation

The Ontario air brake test includes a crucial chapter: “Inspecting Air Brake System Operation.” This section focuses on verifying that the entire air brake system functions properly during regular use.

Ontario Air Brake Test - Chapter 10a: Inspecting Air Brake System Operation

1 / 40

What is the maximum allowable air loss for a tractor with two or more trailers?

41 kPa (6 psi) per minute

55 kPa (8 psi) per minute

28 kPa (4 psi) per minute

21 kPa (3 psi) per minute

2 / 40

When is it safe to leave the driver’s seat or get under a vehicle during inspection?

When air pressure is above 621 kPa (90 psi)

Whenever the engine is off

Only when spring brakes are applied or wheels are securely blocked

Whenever the transmission is in neutral

3 / 40

What indicates that the air compressor has reached cut-out pressure on a vehicle with an air dryer?

The air dryer exhaust cycle

A drop in engine rpm

The service brake lights turning on

A flashing light on the dash

4 / 40

What must you do before starting any air brake inspection on a vehicle?

Leave the engine on and transmission in gear

Park on any surface, apply only the parking brake

Rely on transmission alone to hold the vehicle

Park on level ground, apply spring brakes, and chock/block the wheels

5 / 40

When does the vehicle pass the low air-pressure warning device test?

When the device activates at any pressure

When the device activates at or above 380 kPa (55 psi) on both primary and secondary gauges

When only the primary gauge shows activation

When the device activates below 380 kPa (55 psi)

6 / 40

When does the vehicle fail the air-pressure build-up time test?

When only one gauge increases

When pressure does not drop quickly

When pressure build-up time exceeds two minutes

When pressure build-up time is less than one minute

7 / 40

When does the vehicle pass the governor setting test?

When cut-out is exactly 1000 kPa (145 psi)

When cut-in/out are any values but consistent

When cut-in is exactly 552 kPa (80 psi)

When cut-in/out are within manufacturer range, cut-out < 1000 kPa (145 psi), and cut-in > 552 kPa (80 psi)

8 / 40

How do you determine the cut-out pressure during the governor test?

Turn the engine off and observe pressure drop

Run the engine until pressure stops climbing and note the maximum level

Open the drain valves and time the discharge

Pump the brakes until the warning light comes on

9 / 40

At what minimum pressure must the low air-pressure warning device activate, or it is considered defective?

414 kPa (60 psi)

621 kPa (90 psi)

380 kPa (55 psi)

552 kPa (80 psi)

10 / 40

During the air-pressure build-up test, what engine speed is required?

600 to 900 rpm

Engine off

Above 1,200 rpm

Idle at 400 rpm

11 / 40

To begin the air-pressure build-up time test, to what level must system pressure be reduced?

Below 621 kPa (90 psi)

Below 380 kPa (55 psi)

Below 414 kPa (60 psi)

Below 552 kPa (80 psi)

12 / 40

Under Ontario law, what is the status of operating a vehicle with a defective low air-pressure warning device?

It is allowed only without a trailer

It is allowed for short distances

It is allowed if the driver is careful

It is prohibited

13 / 40

What is the maximum allowable air loss for a tractor and trailer combination?

21 kPa (3 psi) per minute

7 kPa (1 psi) per minute

28 kPa (4 psi) per minute

41 kPa (6 psi) per minute

14 / 40

What is the maximum allowable actual cut-out pressure?

552 kPa (80 psi)

621 kPa (90 psi)

1000 kPa (145 psi)

690 kPa (100 psi)

15 / 40

How do you determine the cut-in pressure during the governor test?

Press and release the brake pedal to lower pressure, then note when pressure begins to rise

Apply the parking brake and see when it holds

Shut off the engine and see when pressure stabilizes

Watch for when the warning device turns off

16 / 40

What must drivers be alert for that indicates possible air brake system leaks?

Steering wheel vibration

Unexplained pressure loss in air tanks when brakes are not used

Increased fuel consumption

Engine coolant temperature changes

17 / 40

What must be the status of the air brake system pressure before the air-loss rate test?

Exactly 690 kPa (100 psi)

Below 380 kPa (55 psi)

Within its normal operating pressure range

At zero kPa

18 / 40

What is the maximum allowable air loss for a straight truck, tractor, or bus?

41 kPa (6 psi) per minute

21 kPa (3 psi) per minute

14 kPa (2 psi) per minute

28 kPa (4 psi) per minute

19 / 40

At approximately what pressure do most low air-pressure warning devices activate?

Above 552 kPa (80 psi)

Exactly 621 kPa (90 psi)

Above 414 kPa (60 psi)

Below 380 kPa (55 psi)

20 / 40

When does the vehicle pass the system air-loss rate test?

When pressure stays exactly the same

When the pressure drop is equal to or less than the specified value for that vehicle

When the pressure drop is greater than the specified value

When only one gauge shows a drop

21 / 40

During the air-loss rate test, what do you do with the brake pedal?

Press it halfway down

Do not touch it at all

Press and hold it fully applied for one minute

Pump it repeatedly for one minute

22 / 40

During the low air-pressure warning test, what must be turned on?

The headlights

The hazard flashers

The engine brake

The ignition switch

23 / 40

Before performing the system air-loss rate test, what must be done with the spring brakes?

They must be half-applied

They must be caged

They must be released

They must be applied

24 / 40

What component controls the cut-in and cut-out pressures in an air brake system?

The relay valve

The air dryer

The air-compressor governor

The foot valve

25 / 40

When is the air brake system considered defective regarding governor settings?

When cut-in is above 1000 kPa (145 psi)

When cut-out is below 690 kPa (100 psi)

When cut-out is above 1000 kPa (145 psi) or cut-in is below 552 kPa (80 psi)

When both cut-in and cut-out are the same

26 / 40

When does the vehicle fail the low air-pressure warning device test?

When the primary gauge alone shows a warning

When the device does not activate or activates below 380 kPa (55 psi) on either gauge

When the device activates at or above 380 kPa (55 psi)

When it activates above 690 kPa (100 psi)

27 / 40

What is not considered in the air-loss rate test?

The final pressure reading after one minute

The engine rpm

The type of vehicle

The initial pressure drop when the brakes are first applied

28 / 40

To test the low air-pressure warning device, from what minimum pressure must you begin the test?

Above 621 kPa (90 psi)

Above 414 kPa (60 psi)

Above 380 kPa (55 psi)

Above 552 kPa (80 psi)

29 / 40

What is the first step before testing the air-compressor governor settings?

Disconnect the trailer

Turn off the ignition

Drain all air tanks completely

Properly secure the vehicle and release the spring brakes

30 / 40

Why must the vehicle be parked on level ground before conducting an air brake inspection?

To make the gauges easier to read

To prevent the vehicle from rolling during the inspection

To cool the air compressor

To improve fuel economy

31 / 40

What does the Ontario Highway Traffic Act say about operating a vehicle with excessive air loss rate?

It is allowed under 40 km/h

It is prohibited

It is allowed only with a special permit

It is allowed for maintenance trips

32 / 40

Approximately how much lower is the cut-in pressure setting than the cut-out pressure setting?

138 to 173 kPa (20 to 25 psi)

200 to 250 kPa (30 to 35 psi)

345 kPa (50 psi)

55 to 70 kPa (8 to 10 psi)

33 / 40

What is the maximum allowable time for pressure to build from 587 kPa (85 psi) to 690 kPa (100 psi)?

One minute or less

Two minutes or less

Three minutes or less

Five minutes or less

34 / 40

In the build-up time test, what is the end pressure at which timing stops?

621 kPa (90 psi)

552 kPa (80 psi)

587 kPa (85 psi)

690 kPa (100 psi)

35 / 40

How do you lower air pressure when testing the low air-pressure warning device?

Turn the engine off and wait

Repeatedly press and release the brake pedal

Open the drain valves

Pump the parking brake

36 / 40

Under Ontario law, what is the status of operating a vehicle with governor settings outside prescribed limits?

It is allowed with reduced speed

It is prohibited

It is allowed only in a yard

It is allowed under supervision

37 / 40

What is the minimum allowable actual cut-in pressure?

690 kPa (100 psi)

552 kPa (80 psi)

414 kPa (60 psi)

380 kPa (55 psi)

38 / 40

In the build-up time test, from what start pressure do you begin timing?

552 kPa (80 psi)

587 kPa (85 psi)

621 kPa (90 psi)

690 kPa (100 psi)

39 / 40

When does the vehicle fail the system air-loss rate test?

When the test lasts less than one minute

When the pressure drop exceeds the value specified for that vehicle

When there is no pressure drop at all

When pressure drops only on the secondary gauge

40 / 40

What does the Ontario Highway Traffic Act say about operating a vehicle that fails to build air pressure within the prescribed time?

It is permitted only with a permit

It is allowed only on secondary roads

It is allowed if the vehicle is empty

It is prohibited

Your score is

Drivers must check the air pressure build-up rate, monitor warning devices, and test the service and parking brakes for responsiveness. The inspection also involves ensuring there are no unusual noises or delays when applying the brakes. Understanding how to identify operational issues is essential for both passing the test and maintaining road safety. Mastery of system operation checks prepares drivers to detect and address problems before they lead to brake failure.