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Mississippi CDL DMV Air Brakes 2

Take 6 practice tests for CDL is the best way to prepare for your Mississippi DMV exam is by taking our free practice tests. The following question are from real Mississippi 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. What color are ABS malfunction lamps?
Orange
Yellow
Green
Blue

Vehicles with Anti-Lock Braking Systems (ABS) have yellow malfunction lamps.

2. The parking brake should be:
Used whenever you park your vehicle.
Used while driving.
Set when driving in bad weather.
Removed.

The parking brake in a vehicle with air brakes should be used every time the vehicle is parked.

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

Truck tractors with air brakes built on or after March 1, 1997 must be equipped with Anti-Lock Braking Systems (ABS).

4. Friction inside a brake drum is caused when the brake shoes and linings:
Push against each other.
Separate from the axle.
Push against the inside of the drum.
Create excess heat.

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.

5. The leakage rate for a triple combination vehicle with air brakes should be no more than ____ in one minute during a static leakage test.
8 psi
5 psi
3 psi

When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 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.

6. Truck tractors with air brakes that were built on or after March 1, 1997 are equipped with:
An extra set of brakes.
Voice-activated brakes.
Cruise control.
Anti-Lock Braking Systems (ABS).

Truck tractors with air brakes that were manufactured on or after March 1, 1997 are required to be equipped with Anti-Lock Braking Systems (ABS). ABS is required in any other type of vehicle with air brakes that was manufactured on or after March 1, 1998.

7. Braking mechanisms are located inside:
The fifth wheel.
A brake drum.
The landing gear.

Drum brakes are attached to the wheels and located on the axles of a vehicle. The braking mechanisms that cause the vehicle to stop can be found inside of a drum brake.

8. Pressing and releasing the brake pedal unnecessarily can:
Release air faster than it can be replaced.
Add more air to a brake system.
Make the brake pedal harder to depress.
Create a loud noise.

On a vehicle with air brakes, pressing and releasing the brake pedal unnecessarily may let air out of the braking system faster than the compressor can replace it. This may cause the system's air pressure to become too low and the brakes to stop working.

9. 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.

10. The service brake system:
Applies and releases the brakes when you press the brake pedal while driving normally.
Applies and releases the parking brakes.
Applies and releases the emergency brake.
Applies and releases the axle brake.

Air brakes consists of three separate braking systems: the service brake system, the parking brake system, and the emergency brake system. The service brake system applies and releases the brakes when you use the brake pedal while driving normally.

11. To make a stop in a vehicle using air brakes, the driver should:
Press down the brake pedal.
Lift the brake pedal toward them.
Push in the brake knob.
Pull out the brake knob.

To make a normal stop in an air-braked vehicle, push the brake pedal down and control the pressure so that the vehicle comes to a smooth, safe stop.

12. 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.

13. If using air tanks with manually operated drains, how often should you drain the tanks?
Every day
Once a week
Once a month
Once every six months

In an air brake system with manually operated drains, the tanks should be drained at the end of each day of driving.

14. Air tank drains:
Allow rain water to enter air tanks.
Are used to drain water and oil from air tanks.
Should never be opened.
Must remain open while driving.

In an air brake system, the air tanks are equipped with drains that allow water and compressor oil to be removed from the system. If allowed to build up, water and compressor oil can damage an air brake system.

15. All air tanks must include:
A drain valve.
A lock.
A trap door.
A warning sticker.

Air brake system tanks must contain drain valves. These valves are used to drain accumulated oil and water from the tanks and may be either manually or automatically operated.

16. What is removed when an air tank is drained?
Water and oil
Ammonia
Liquid cleaners

In an air brake system, air tanks have drains to remove accumulations of water and compressor oil. Allowing water and oil to accumulate in the system could cause damage to the brakes.

17. To stop a vehicle using air brakes:
The brake pedal should be pressed.
The brake pedal should be lifted.
The brake knob should be pulled out.
The brake knob should be pushed in.

To stop normally in a vehicle with air brakes, press down the brake pedal.

18. 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.

19. If an air compressor is belt-driven, the belt should be routinely checked to ensure that it is:
Thin.
Properly tightened.
Cracked.

If your vehicle has air brakes, the air compressor drive belt should be checked before each drive. Check the tightness of the belt and verify that it is in good condition.

20. 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.

21. During an applied leakage test, the maximum leakage rate for a triple 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 triple combination should have a leakage rate no higher than 6 psi in a minute during an applied leakage test.

22. Before driving a vehicle with a dual air brake system, you must wait for the air compressor to build a minimum of ____ in both the primary and secondary systems.
25 psi
50 psi
75 psi
100 psi

Before driving a vehicle with a dual air brake system, you should wait for the air compressor to build up at least 100 psi in both the primary and secondary systems.

23. In a dual air brake system, air pressure should build from 85 to 100 psi within ____ seconds.
25
10
45

When inspecting a vehicle with a dual air brake system, you should wait for air pressure to build from 85 to 100 psi in both the primary and secondary systems. This should take about 45 seconds.

24. In a vehicle with dual air brakes, what happens if one system is low on pressure?
The air from the other system will be used to supplement the system with the low pressure.
The front or rear brakes may not work properly.
All brakes will be inoperable.
The low system will use an auxiliary system to fill the tank.

In a dual air brake system, if one of the air systems gets very low on pressure, either the front or rear brakes will not be operating fully. You should bring your vehicle to a safe stop and have the air system repaired.

25. What does the air compressor governor do?
Controls when the air compressor pumps air into the air storage tanks.
Controls how quickly air leaves the air storage tanks.
Controls the temperature of the air entering the air storage tanks.
Controls the temperature of the air leaving the air storage tanks.

In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.

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