Air Brake Test Questions And Answers

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7 - Air Brake Test

Practice Test - 7

30 Questions

Passing Marks - 80%

1 / 30

A tractor protection valve:

Causes towing vehicle spring brakes to apply in an emergency

Prevents air loss from the trailer supply line

Causes the trailer service brakes to apply in an emergency

Prevents loss of air out of the towing vehicle

2 / 30

When should you drain the air tanks?

Daily

Monthly

Only when water is visible

Weekly

3 / 30

When air brakes are applied or released, the brakes will respond:

After a split-second delay

Directly and immediately

Slower at slow speed

Faster at high speed

4 / 30

Air brake chamber pushrod stroke is the result of:

Compressed air entering the brake chamber

Compressed air entering the air tanks

Brakes that are out of adjustment

Moisture entering the air tanks

5 / 30

To prevent vehicle movement during an inspection of the air brake system, a driver should use:

The service brakes

Wheel chocks and blocks

The spring brakes

The brake pedals

6 / 30

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

Reduced stopping distance

Reduced heat generation

Increased demand on brake pressure

Increased brake efficiency

7 / 30

When inspecting the brake chambers on each side of steering axle, the driver must ensure that slack adjusters are :

Not the same effective length and brake chambers are the same

The same effective length and brake chambers are not the same size

Not the same size and brake chambers are not the same effective length

The same effective length and brake chambers are the same size

8 / 30

When inspecting brake drums and rotors, the driver must look for:

Brake callipers or rotors that are not the same color

Square parts and marking

Broken or cracked brake drums or roots

Brake drums or shoes that are not the correct size

9 / 30

At what pressure must the low air-pressure warning device activate?

Below 200 kPa (30 psi)

At or above 380 kPa (55 psi)

Above 414 kPa (60 psi)

Exactly 500 kPa (75 psi)

10 / 30

Why is it important to regularly inspect the slack adjusters?

To increase air tank efficiency

To maintain governor settings

To prevent over-lubrication

To ensure proper brake adjustment

11 / 30

How can drivers recognize a failing air compressor?

educed governor cut-out pressure

Overly sensitive brake pedal response

Excessive air tank moisture

Increased build-up times

12 / 30

What is the purpose of the air compressor governor?

To adjust relay valve timing

To increase brake chamber efficiency

To vent excess pressure from tanks

To regulate when the compressor starts and stops

13 / 30

When air brake system pressure drops below 414 kPa (60psi), the spring brakes:

Must be manually applies

Massey manual released

Will automatically releases

Will automatically applies

14 / 30

A brake having an exposed pushrod is out of adjustment when:

All pressure drops more than 55 kPa (8 psi) when brakes are applied

The angle between the slack adjuster and pushrod is more than 90 degrees

The pushrod stroke exceeds the adjustment limit of the brake chamber

The angle between the slack adjuster and pushrod is less than 90 degrees

15 / 30

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

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

It must be corrected the next time the vehicle serviced

16 / 30

What should be done if the parking brake fails to engage?

Check spring brake chambers for defects

Drain wet tank moisture

Adjust pushrod stroke

Inspect relay valve timing

17 / 30

What is the purpose of brake linings in drum brakes?

To reduce air pressure

To increase brake chamber life

To provide friction for stopping

To regulate pushrod movement

18 / 30

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

21 kPa (3 psi) per minute

7 kPa (1psi) per minute

55 kPa (8 psi) per minute

41 kPa (6psi) per minute

19 / 30

What component prevents over-pressure in the air brake system?

Governor

Slack adjuster

Air compressor

Safety valve

20 / 30

What is the function of the emergency brake system?

To stop the vehicle in case of service brake failure

To prevent wheel lockup

To regulate air dryer operation

To increase trailer stability

21 / 30

What is the purpose of an air dryer in an air brake system?

Remove moisture from the air

Store compressed air

Increase air pressure

Reduce engine load

22 / 30

What is the function of the modulator valve in ABS?

To prevent moisture build-up

To control air pressure at each wheel

To increase parking brake efficiency

To regulate air tank capacity

23 / 30

How often should spring brakes be checked for proper operation?

During every pre-trip inspection

Weekly

Only when issues arise

Monthly

24 / 30

Using anti-lock braking systems (ABS) to prevent the wheels from locking:

Causes for steering and directional stability in all driving situations

Help maintain steering control during emergency braking

Can cause loss of steering control

Causes the brakes to go out of adjustment more easily

25 / 30

What should a driver observe during a service brake application test?

Brake pedal travel and air loss

Air dryer operation

Moisture level in air tanks

Governor cut-out pressure

26 / 30

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

The vehicle must be driven only on secondary roads

The vehicle may not be driven on any road or highway

The vehicle must be driven to the nearest service center

The vehicle must be driven slowly on the highway

27 / 30

Trailer couplers or 'glad hands' are usually:

Yellow and black to avoid cross-connection

Color-matched and designed to prevent cross-connection

Cross-connected when colors are matched

Painted the same color as the vehicle

28 / 30

What should you inspect on brake hoses and tubes during an air brake check?

Manufacturer's label

Proper installation angle

Color coding

Leaks, cuts, or abrasions

29 / 30

Air compressors:

All the above

Force air into a smaller space

Are filled with brake fluid

Generate heat to stop a vehicle

30 / 30

The compressed air in an air brake system is stored in:

The air compressor governor

The air lines and valves

The brake chambers

The vehicle's air tanks

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