Air Brake Practice Exam - The Drive Test

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4 - Air Brake Test

Practice Test - 4

30 Questions

Passing Marks - 80%

1 / 30

What is the purpose of the dual-service air tanks in an air brake system?

To reduce air pressure fluctuations

To store extra air for emergencies

To separate primary and secondary air systems

To provide backup in case of compressor failure

2 / 30

hy are "S" cam brakes commonly used in commercial vehicles?

They provide reliable braking force

They are lighter than other systems

They are easier to install

They require no maintenance

3 / 30

When inspecting the air compressor, the driver must look for:

Improper governor setting

All the above

Loose air tank brackets or fasteners

Insecure mounting brackets or fasteners

4 / 30

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

Will automatically releases

Must be manually applies

Massey manual released

Will automatically applies

5 / 30

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

Directly and immediately

Faster at high speed

After a split-second delay

Slower at slow speed

6 / 30

What might indicate a damaged brake chamber diaphragm?

Increased air pressure

Longer service brake life

Reduced spring brake effectiveness

Excessive air loss during brake application

7 / 30

Why is it essential to avoid over-adjusting slack adjusters?

It allows the air compressor to work harder

It can reduce brake lining wear

It can cause brakes to drag or overheat

It can increase brake efficiency

8 / 30

A properly functioning air brake system:

Should not have many noticeable air leaks

Has many noticeable air leaks

Will loose air at a noticeable rate when the engine is not running

Will loose air at a noticeable rate

9 / 30

What is the minimum allowable air pressure for a tractor-trailer combination before driving?

552 kPa (80 psi)

690 kPa (100 psi)

414 kPa (60 psi)

828 kPa (120 psi)

10 / 30

What is the primary function of the supply (wet) tank in an air brake system?

To collect moisture and contaminants

To reduce air pressure fluctuations

To store compressed air for emergency use

To operate the parking brakes

11 / 30

What is the function of the air dryer’s purging system?

To clean the air tanks

To increase air pressure

To cool the air compressor

To remove moisture and contaminants

12 / 30

At what point does the air compressor governor cut in?

At 552 kPa (80 psi) or higher

When tank is half full

Below 552 kPa (80 psi)

At 100 psi exactly

13 / 30

Manually-operated front wheel limiting valves are:

Used to reduce the force of the service brakes on the front steering axle

Used to reduce the brakes force on trailer axle brakes

Used to limit the number of times that brakes can be applied

Only found on new vehicles to disable front steering axle brakes

14 / 30

Brakes convert the energy of a moving vehicle into:

Water

Heat

Noise

Compressed air

15 / 30

To test the low air warning device, the ignition switch must be turned on and air pressure must be:

Reduce from 414 kPa (60 psi) until the device de-activates

Reduce from the normal operating range until the device activates

Raise from 0 until the de-activates

Raised from the normal operating range until the device activates

16 / 30

What type of braking system is required for medium-duty vehicles with air-over-hydraulic brakes?

Anti-lock brake certification

Air brake endorsement

Spring brake certification

Hydraulic brake endorsement

17 / 30

The type of air brake components on most large commercial vehicles are either:

Air or disc brakes

Drum or disc brakes

Wet or dry brakes

Drum or hydraulic brakes

18 / 30

The brake system on most large commercial vehicle use:

Brake fluid to apply the brakes

Water to apply the brakes

Steam to apply the brakes

Compressed air to apply the brakes

19 / 30

What component combines service brake and parking brake functionality?

Disc brake chamber

Spring brake chamber

Dual air tank

Alcohol evaporator

20 / 30

Safety valves prevent:

Draining of the air tanks

Loss of air tanks

Overheating of the air tanks

Overpressure of the air brake system

21 / 30

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

Manufacturer's label

Leaks, cuts, or abrasions

Color coding

Proper installation angle

22 / 30

When a low air pressure warning device activates, the driver must:

Replace the warning device

Drain the moisture out of the supply (wet) tank

Drive the vehicle until brakes come on automatically

Come on a safe stop as soon as possible

23 / 30

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

Moisture level in air tanks

Air dryer operation

Brake pedal travel and air loss

Governor cut-out pressure

24 / 30

Air compressor cut-in pressure must be less than:

414 kPa (60 psi)

828 kPa (120 psi)

525 kPa (80 psi)

932 kPa (135 psi)

25 / 30

The part inside a spring brake chamber can be hazardous if the:

Released pushrod

Rubber diaphragm

Large coil spring

Return spring

26 / 30

How do anti-lock braking systems (ABS) enhance vehicle safety?

By preventing wheel lockup

By reducing air loss

By increasing brake power

By shortening stopping distance

27 / 30

How should a driver check for air leaks in the system during a static test?

Rev the engine to maximum RPM

Watch the air dryer for excessive purging

Listen for audible leaks with the engine off

Apply parking brakes

28 / 30

To test air pressure build-up-time, the engine must be running at:

600 to 900 rpm

400 to 500 rpm

2000 to 2100 rpm

1000 to 1500 rpm

29 / 30

An air dryer removes moisture, which is expelled when the:

Driver applies the service brakes

Low air warning devices activates

Compressor reaches cut-out pressure

Spring brakes are applied

30 / 30

What is the purpose of the one-way check valve in an air brake system?

To prevent moisture accumulation

To regulate air compressor cut-out

To release spring brakes faster

To stop air from flowing back into the supply tank

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