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

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

The supply line is repaired

The warning light goes out

The system is recharged

The pressure in the trailer reservoir and lines is drained off

2 / 30

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

120 psi

90 psi

60 psi

75 psi

3 / 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?

The one-way check valve

The two-way check valve

The dead-end valve

None of these

4 / 30

Which trailers have a manual supply valve?

Older

Tandem

Only Class 4 vehicles

Newer

5 / 30

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

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

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

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

6 / 30

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

Air pressure is still being generated by the compressor

None of these

Air pressure remains within the trailer system

There is still air in the hoses

7 / 30

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

The speed gets reduced

A brake application is made

The line gets repaired

All of the above

8 / 30

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

Yes

Only if left in low gear

Yes, provided the engine is running

9 / 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

10 / 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

11 / 30

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

A full brake lock-up

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

A full brake fade

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

12 / 30

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

Up and down

Normal and emergency

Fast and slow

Rough and smooth

13 / 30

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

The slack adjusters must be used

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

All of the above

Exhaust the air pressure

14 / 30

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

The service brakes applied

The wheels blocked to prevent a possible runaway

Hazard lights on

The vehicle placed in the lowest gear

15 / 30

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

The secondary reservoir

The trailer reservoir

The primary reservoir

The supply reservoir

16 / 30

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

A one-way check valve

Safety valve

Trailer relay valve

A two-way check valve

17 / 30

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

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

Nothing would happen

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

The brakes lock up

18 / 30

Spring parking brakes serve as a means of what?

Securing a parked trailer attached to a tractor

Partially securing the trailer when it is attached to a tractor

Assisting the service brake with braking

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

19 / 30

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

The foot valve doesn't push the air

Air is lost in both circuits

The air lines are too small

The compressor is slow

20 / 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 2 vehicles

Only for Class 3 vehicles

Yes

21 / 30

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

The brakes would lock

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

All of the above

The safety chain would keep it together

22 / 30

.The spring parking brakes are applied with what?

Hydraulic pressure

Cable pressure

Air pressure

Spring pressure

23 / 30

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

Front service reservoirs only

Relay valve

Spring parking brake chambers

Trailer spring parking brake valve

24 / 30

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

How many brake chambers need the air pressure

How much air was in the tank

How big the brake chambers are

How airtight the system is

25 / 30

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

Two sections

One section, but larger

Four sections

Three sections

26 / 30

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

A faster compressor

Larger supply tanks

Larger air hoses

The trailer reservoir and relay emergency valve

27 / 30

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

None of these

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

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

Pushes the air away

28 / 30

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

The secondary circuit

The spring brakes

The governor

None of these

29 / 30

What is known as charging the trailer system?

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

The air hoses will stiffen as air runs through them

All of the above

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

30 / 30

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

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

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

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

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

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Air Brake Practice Test 06

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