Air Brake Practice Test 06

By practicing and familiarizing yourself with the types of questions that are likely to appear on the real test, you’ll be able to approach the exam with greater confidence and competence. With proper preparation and focus, you can pass your official air brake exam with flying colors and secure your license to drive heavy commercial vehicles.

1 / 30

With a dual air brake system, the vehicle will continue to have braking ability unless...

The compressor is slow

The air lines are too small

Air is lost in both circuits

The foot valve doesn't push the air

2 / 30

.The spring parking brakes are applied with what?

Air pressure

Spring pressure

Cable pressure

Hydraulic pressure

3 / 30

How long the air in the system will hold the brakes applied depends on what?

How much air was in the tank

How many brake chambers need the air pressure

How big the brake chambers are

How airtight the system is

4 / 30

Which statement is false? A trailer with spring parking brakes has these components...

Spring parking brake chambers

Front service reservoirs only

Relay valve

Trailer spring parking brake valve

5 / 30

One section of this dual foot valve controls the primary circuit and the other controls...

The spring brakes

The secondary circuit

None of these

The governor

6 / 30

Blended air is air taken from the primary and secondary circuits through...

Trailer relay valve

A two-way check valve

Safety valve

A one-way check valve

7 / 30

Which of the following is not a function of the relay emergency valve?

It has a one-way check valve which stops air pressure in the reservoir from going back to the source of the supply

It stops the driver at anytime from operating the cab-mounted trailer supply valve to cause an emergency application of the trailer brakes

It directs trailer reservoir air pressure to the trailer brakes, causing an emergency application of the brakes

It relays air from the trailer reservoir to the trailer brake chambers during a brake application

8 / 30

If the foot valve is released and the hand valve is applied, what happens?

The brakes lock up

Nothing would happen

The shuttle in the two-way check valve would shift and application air would apply the trailer brakes only

The shuttle in the two-way check valve would shift and application air would apply the tractor brakes only

9 / 30

The release of the foot or hand valve stops the flow of application air and the relay portion of the valve goes where?

Opens up, increasing the flow of air back to the tanks

Returns to its original position, stopping the flow of air pressure

None of these

Pushes the air away

10 / 30

Which statement is false? The trailer brakes will remain applied until..

The system is recharged

The warning light goes out

The supply line is repaired

The pressure in the trailer reservoir and lines is drained off

11 / 30

Rupture of the compressor discharge line would result in loss of air pressure from which reservoir?

The primary reservoir

The trailer reservoir

The supply reservoir

The secondary reservoir

12 / 30

Is there sufficient reservoir air pressure in the primary reservoir for a limited number of brake applications to stop the vehicle before the spring parking brakes are activated?

Only for Class 3 vehicles

Yes

Only for Class 2 vehicles

13 / 30

As a safety precaution, parked trailers without spring parking brakes should always have what?

The wheels blocked to prevent a possible runaway

The vehicle placed in the lowest gear

The service brakes applied

Hazard lights on

14 / 30

For a dual air brake system, the foot valve is divided into...

Three sections

Four sections

One section, but larger

Two sections

15 / 30

A sudden loss of air pressure in the supply line will trigger the relay emergency valve which causes what?

The trailer reservoir to dump its air directly to the trailer brake chambers

A full brake fade

Stop air flow and push it back through the two-way valve

A full brake lock-up

16 / 30

Spring parking brakes serve as a means of what?

Assisting the service brake with braking

Securing a parked trailer whether it is attached to a tractor or not

Securing a parked trailer attached to a tractor

Partially securing the trailer when it is attached to a tractor

17 / 30

If there's a loss of reservoir air pressure ,what prevents the reservoir air pressure in the primary reservoir from escaping back to the supply reservoir and the ruptured line?

None of these

The one-way check valve

The two-way check valve

The dead-end valve

18 / 30

To move a trailer that has been parked with the brakes in an emergency application, what has to happen?

All of the above

It is necessary to charge the system to release the trailer brakes

The slack adjusters must be used

Exhaust the air pressure

19 / 30

With the manual trailer supply valve, the trailer brakes will remain applied only as long as what?

None of these

Air pressure remains within the trailer system

There is still air in the hoses

Air pressure is still being generated by the compressor

20 / 30

What system are more heavy-duty vehicles using now?

Air-over hydraulic system

Dual air brake system

None of these

Singular air brake system

21 / 30

Which statement is false? The trailer spring parking brake valve is responsible for several important functions, including...

It will automatically apply the spring parking brakes if supply pressure is rapidly lost

It controls the application and release of the trailer's spring brakes

It allows automatic spring brake application if the trailer supply line has a gradual leak

It protects and isolates the front service reservoir from the rear service reservoir

22 / 30

Which trailers have a manual supply valve?

Newer

Tandem

Only Class 4 vehicles

Older

23 / 30

What is known as charging the trailer system?

Pressure will build up in the trailer reservoir to the same pressure as the reservoirs on the tractor

All of the above

The compressor will force more air into the control line, ready for the trailers

The air hoses will stiffen as air runs through them

24 / 30

If the control line is ruptured or disconnected, no action will take place until...

All of the above

A brake application is made

The speed gets reduced

The line gets repaired

25 / 30

What are the two positions the manual trailer supply valve has?

Up and down

Fast and slow

Rough and smooth

Normal and emergency

26 / 30

If a trailer that is not equipped with spring parking brakes were to separate from the tractor, what would happen?

The safety chain would keep it together

All of the above

The control line and the supply line would detach from the tractor

The brakes would lock

27 / 30

In the event of tractor reservoir air loss, the trailer supply valve must be shifted to what?

The emergency position manually

The normal position manually

The down position manually

The smooth position manually

28 / 30

Should trailer brakes be used to hold a parked vehicle that is left unattended?

Only if left in low gear

Yes, provided the engine is running

Yes

29 / 30

The trailer supply valve should be open when the tractor pressure has built up to approximately how many psi?

60 psi

90 psi

120 psi

75 psi

30 / 30

During foot or hand valve brake application, brake lag time has been minimized with the addition of what?

Larger air hoses

A faster compressor

The trailer reservoir and relay emergency valve

Larger supply tanks

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Air Brake Practice Test 06

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