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Arizona CDL DMV Air Brakes 2

Take 6 practice tests for CDL is the best way to prepare for your Arizona DMV exam is by taking our free practice tests. The following question are from real Arizona DMV practice test. More than 95% people pass a DMV exam when practice at DMV Practice Test.

Number of Test
6
Number of Question
25
Passing score
20
13%
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  • 0Incorrect
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Ouch! While you were on a roll there for a few questions, you didn’t pass this time. But I know this test, and I think you’ll pass next time. Really.

1. Failing to drain air tanks could result in:
Water accumulations freezing and causing brake failure.
Squishy brakes.
Too much air collecting in the tanks.

In an air brake system, the air tanks must be periodically drained to remove accumulations of water and compressor oil. If water is not removed, it could freeze in cold weather and cause brake failure.

2. When leaving your vehicle unattended:
The parking brake must be always be used.
The parking brake should never be used.
Windows in the cab should be lowered.

Always apply the parking brake when leaving your vehicle unattended.

3. Some water and compressor oil is usually found in the compressed air within an air brake system. The water and compressor oil:
Are necessary for the proper function of the system.
Should take up about 10 percent of the tank.
Should be removed regularly.

If water and compressor oil are left to build up in an air brake system, the system can be damaged. Air storage tanks are equipped with drains to allow this accumulation to be removed. Manually controlled drains should be operated at the end of each day of driving.

4. If the low air pressure warning signal comes on in a vehicle with air brakes, the driver should:
Test the brakes while driving, but continue driving if nothing seems wrong.
Immediately stop driving.
Drive with the hazard lights activated.

If the low air pressure warning signal comes on while you are operating a vehicle with air brakes, you should stop and safely park the vehicle as soon as possible. It is essential that you are able to stop safely while you still have some braking power remaining.

5. An emergency brake must be controlled by:
Mechanical force.
Air pressure.
Gravity.

All trucks, truck tractors, and buses must be equipped with emergency brakes and parking brakes. Because air pressure can eventually leak away, emergency and parking brakes should be held on by mechanical force.

6. The air compressor is connected to the:
Transmission.
Engine.
Radiator.

The air compressor of an air brake system is connected to the engine through gears or a v-belt. The compressor may be air-cooled or cooled by the engine cooling system.

7. When leaving a vehicle unattended, a driver should:
Always set the parking brake.
Only set the parking brake if the vehicle is parked on a slope.
Deflate the tires by 10 percent.

Always apply the parking brake when leaving your vehicle unattended.

8. Air tank drains:
Should not be used in cold weather.
Are helpful to remove water and oil from the air tanks.
Are used to move air to the brakes.

Compressed air in an air brake system usually has a certain amount of water and oil in it. This can harm the system if allowed to accumulate. Air tanks have drain valves to aid in removing water and oil from the compressed air.

9. If you are driving and the ABS light comes on, it means that the ABS:
Cannot work due to weather conditions.
Has just been activated.
Is not working properly.

ABS malfunction lamps indicate that something in the Anti-Lock Braking System is not working properly.

10. A low air pressure warning signal:
Is not required on vehicles with air brakes.
Is required on vehicles with air brakes.
Is optional on vehicles with air brakes.

A vehicle with air brakes must be equipped with a low air pressure warning signal. If the warning signal goes off while a vehicle is being driven, the driver should bring the vehicle to a complete stop and have the system repaired.

11. What do the two systems of a dual air brake system share?
Hoses
An air compressor
Air tanks

Both systems in a dual air brake systems share a single air compressor. If the air compressor is damaged, neither system will be able to operate properly.

12. A safety valve is set to open at ____ pounds per square inch (psi).
100
150
200

The safety valve protects air tanks and the rest of an air brake system from accumulating too much air pressure. The safety valve is usually set to open at 150 psi.

13. In a dual air brake system, if one air system is very low on pressure:
None of the brakes will work at all.
Either the front or rear brakes will not be fully operable.
There is usually no noticeable effect.

In a dual air brake system, either the front or rear brakes will not be fully operable if one of the air systems gets too low on pressure. If the air pressure in either tank gets too low while you are driving, you should exit the road and park as soon as possible.

14. Alcohol evaporators are:
Illegal.
Used to add alcohol to braking systems to prevent items from freezing.
Only allowed on vehicles carrying hazardous materials.

Some air brake systems include an alcohol evaporator. The evaporator introduces alcohol into the braking system to prevent the formation of ice, which can cause damage.

15. Truck tractors with air brakes built on or after March 1, 1997 must have:
An Anti-Lock Braking System (ABS).
Bluetooth.
A GPS.

Truck tractors with air brakes built on or after March 1, 1997, and other vehicles with air brakes built on or after March 1, 1998, must be equipped with anti-lock brakes.

16. What kind of force do emergency brakes use?
Air pressure
Mechanical
Heavy

Air brakes are really three different braking systems: the service brake, the parking brake, and the emergency brake. Emergency and parking brakes are applied with mechanical force.

17. The ____ between an air compressor and reservoir tank prevents air from escaping if the air compressor has a leak.
Slack adjuster
One-way check valve
Tractor protection valve

A one-way check valve is required to be between an air compressor and the first main reservoir. This valve prevents air from escaping the system if the air compressor develops a leak.

18. During a static leakage test, what is the maximum leakage rate that is safe for a double combination vehicle?
3 psi in one minute.
6 psi in one minute.
8 psi in one minute.

When performing a static leakage test on a double combination vehicle with air brakes, the leakage rate should be no more than 3 psi in one minute. If the air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

19. Brakes out of adjustment will:
Work properly.
Cause some of the brakes to overwork and malfunction.
Allow better acceleration.

Brakes out of adjustment will fade before those that are properly adjusted. Brake adjustment must be checked frequently to help prevent brake issues.

20. Friction in an S-cam brake is caused when the brake shoes and linings:
Press against the outside of the brake drum.
Press against the inside of the brake drum.
Push against each other.

Friction inside a brake drum is caused when the brake shoes and linings push against the inside of the drum. The friction in the drums will slow and stop the vehicle.

21. In a vehicle with dual parking control valves, a separate air tank can be used:
To make the air brakes work more effectively.
To temporarily release the spring brakes.
To charge the brakes on the rear trailer.

In a vehicle with dual parking control valves, there is a separate air tank that can be used to temporarily release the spring brakes if they have been activated due to low air pressure. Pushing in the proper control will release the spring brakes for a short period of time, allowing the driver to move the vehicle in an emergency.

22. What do air brakes use to make the brakes work?
Compressed air
Outside air
Non-compressed air

Many large CMVs are equipped with air brakes. An air braking system uses compressed air to operate.

23. Lights that indicate that anti-lock brakes are not working are:
Gray.
Blue.
Yellow.

Vehicles equipped with Anti-Lock Braking Systems (ABS) have yellow malfunction lights to indicate issues in the braking system.

24. During an applied leakage test, the maximum leakage rate for a double combination vehicle is ____ in a minute.
2 psi
4 psi
6 psi

It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.

25. Alcohol evaporators are:
Illegal.
Used to introduce alcohol into air brake systems.
Only allowed in the northern parts of the state.

Some air brake systems have alcohol evaporators, which introduce alcohol into the braking system to help prevent the formation of ice.

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