Air Brake Test Practice Questions

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5 - Air Brake Test

Practice Test - 5

30 Questions

Passing Marks - 80%

1 / 30

The air loss rate on a towing vehicle with two or more trailers must not exceed:

41 kPa (6 psi) per minute

55 kPa (8 psi) per minute

28 kPa (4 psi) per minute

7 kPa (1 psi) per minute

2 / 30

Every reliable method for inspecting brake adjustment on a brake having an exposed pushrod is:

Rolling the vehicle forward and applying the brakes

Checking for a 90-degree angle when brakes are applied

Measuring the applied pushrod stroke

Checking air pressure drop on brake application

3 / 30

While draining a vehicle air tanks, the driver must watch the:

Discharge from the air tank of abnormalities

Trailer supply line for air exhausting

Discharge of air from the trailer service line

Function of the governor cut-out

4 / 30

Trailer spring brakes must apply automatically when the:

Trailer supply valve is opened (pushed in)

Spring break valve is opened (pushed in)

Trailer hand valve is released

Trailer supply valve is closed (pulled out)

5 / 30

What should a driver do when the air pressure drops below 552 kPa (80 psi)?

Stop the vehicle immediately

Reduce speed gradually

Apply the hand valve

Drain the air tanks

6 / 30

What is the normal range for air compressor cut-out pressure?

690-828 kPa

300-500 kPa

100-200 psi

552-1000 kPa

7 / 30

When a driver finds a brake that is out of adjustment:

It must be corrected the next time the vehicle serviced

It must be corrected at the next annual inspection

It must be corrected before entering an inspection station

The vehicle must not be driven or operated on any road or highway

8 / 30

What happens when moisture accumulates in the air brake system?

Air pressure rises above normal

Brake linings wear faster

Risk of freezing in cold weather

The brake efficiency increases

9 / 30

Which system ensures braking ability even if one circuit fails?

Single-service system

Air-over-hydraulic system

Spring brake system

Dual-service system

10 / 30

When should you drain the air tanks?

Daily

Monthly

Weekly

Only when water is visible

11 / 30

What is the function of the governor in an air brake system?

To control cut-in and cut-out pressures

To adjust brake shoe position

To prevent wheel lockup

To compress air for storage

12 / 30

What should you do if the air compressor takes more than 2 minutes to build pressure from 85 psi to 100 psi?

Report the system as defective

Increase engine RPMs

Continue driving cautiously

Adjust the governor manually

13 / 30

What is the effect of overloading a vehicle on the brake system?

Reduced heat generation

Increased brake efficiency

Reduced stopping distance

Increased demand on brake pressure

14 / 30

An air tank drain valve that fails to function:

Indicates a defective brake pedal

Is a normal condition of the air brake system

Is a defect of the air brake system

Indicates a defective air compressor governor

15 / 30

If a vehicle moves while the spring brakes are applied, the vehicle has:

Properly adjust spring brakes

A defective brake pedals

Defective spring brakes

Properly adjusted service brakes

16 / 30

When air loss from air brake system exceeds the prescribed limits:

The vehicle must be driven slowly on the highway

The vehicle must be driven to the nearest service center

The vehicle must be driven only on secondary roads

The vehicle may not be driven on any road or highway

17 / 30

What is the role of the alcohol evaporator in the air brake system?

To prevent freezing in cold weather

To regulate cut-in pressure

To remove oil from the system

To clean the compressed air

18 / 30

Which factor can lead to brake fade?

Proper brake adjustment

Cold weather conditions

Overheating due to excessive use

Regular brake maintenance

19 / 30

To test the tractor protection valve, the driver must check for air exhausting from the:

Trailer service line with the trailer supply valve closed (pulled out)

Trailer service line with the trailer supply valve open (pushed in)

Trailer supply line with the trailer air supply valve closed (pulled out)

Trailer supply line with the trailer air supply valve open (pushed in)

20 / 30

What must a driver check during an air brake system inspection?

Engine oil levels

Brake chamber pushrod stroke

Fuel tank levels

Tire pressure

21 / 30

When measuring the applied pushrod stroke on brakes having exposed pushrods, air pressure must be between :

414 and 828 kPa (60 and 120 psi)

690 and 828 kPa (100 and 120 psi)

621 and 690 kPa (90 and 100 psi)

690 and 932 kPa (100 and 135 psi)

22 / 30

To test the spring brakes, the driver should apply them and attempt to move the vehicle by:

Applying the service brakes in any gear

Releasing the spring brakes in any gear

Applying full engine power in a high gear

Applying engine-powered gently in a low gear

23 / 30

What is the purpose of the "wig wag" low air-pressure warning device?

To release spring brakes

To maintain cut-in pressure

To adjust air pressure automatically

To visually warn the driver of low air pressure

24 / 30

The air loss rate on a single vehicle (bus, tractor or truck) must not exceed :

7 kPa (1psi) per minute

41 kPa (6psi) per minute

21 kPa (3 psi) per minute

55 kPa (8 psi) per minute

25 / 30

How are air brakes applied in a trailer during an emergency?

Manually by caging the spring brakes

Automatically by spring brakes

By the tractor parking brake

By pulling the trailer hand valve

26 / 30

What component is used to determine air tank pressure levels?

Pressure release valve

Air pressure gauge

Governor

Compressor regulator

27 / 30

An air compressor governor should cut-in approximately 138 to 173 kPa (20-25 psi):

Below cut-in pressure setting

Above cut-in pressure setting

Below cut-out pressure setting

Above cut-out pressure setting

28 / 30

What is the role of the tractor protection valve?

To protect the tractor air supply from a trailer disconnection

To release the spring brakes automatically

To prevent air loss from the trailer system

To control service brake application

29 / 30

A tractor protection valve is defective if the trailer supply valve is closed (pulled out) and air exhausts from the:

Trailer service line with the brake pedal released

Trailer supply line with brake pedal pressed

Trailer supply line with brake pedal released

Trailer service line with the brake pedal pressed

30 / 30

When an air brake system is defective you must:

Drive vehicle to the nearest service station

Drive the vehicle back to the terminal

Not drive or operate the vehicle on any road or highway

Drive the vehicle slowly on the highway

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