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North Dakota CDL DMV Air Brakes 1

Take 6 practice tests for CDL is the best way to prepare for your North Dakota DMV exam is by taking our free practice tests. The following question are from real North Dakota 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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1. A one-way check valve:
Drains the water and compressor oil from the air tanks.
Prevents air from escaping if the air compressor has a leak.
Activates the emergency brakes when there is a leak.
Holds the spring brakes in position until they are used.

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.

2. During a walk-around inspection, ensure there are no cracks on the brake drums that are more than ____ of the width of the friction area.
One half
One quarter
One third
One tenth

Before beginning a trip, it is important to check the brake drums during your walk-around inspection. It is unsafe to drive if any brake drum has a crack more than one half of the width of the friction area.

3. If the low pressure warning light comes on while you are driving:
Braking will only occur if there is enough air in the tanks.
You can brake 14 times before the air in the system runs out.
You should continue to drive normally and check the brake system when it is convenient.
You should continue driving, but turn the emergency flashers on to warn other motorists.

If the low air pressure warning light turns on, you should stop and safely park your vehicle as soon as possible. Controlled braking will be possible only as long as enough air remains in the tanks.

4. The air entering air storage tanks may contain:
Water and compressor oil.
Frost.
Gravel.
Antifreeze.

The air that enters air storage tanks in an air brake system usually contains a certain amount of water and compressor oil. Because accumulations of these materials can damage the braking system, tanks are equipped with drains to allow their removal.

5. 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.

6. If one air system in a dual air brake system is very low on pressure:
None of the brakes will work at all.
Either the front or rear brakes will not be operating fully.
There will be no noticeable affect.
Lights on the outside of the tractor will flash.

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.

7. At what psi is the safety valve set to open?
100 psi
150 psi
200 psi
500 psi

In an air brake system, the first tank that receives compressed air has a safety valve that releases air if the pressure gets too high. It is usually set to open at 150 psi. If the valve must open, there is a fault in the system that should be repaired by a mechanic.

8. If the air pressure warning light comes on, you should:
Continue to drive normally.
Drive with one foot on the accelerator and one foot on the brake pedal.
Call the local law enforcement agency.
Safely exit the roadway and stop.

If the low air pressure warning signals activate, it is essential that you bring the vehicle to a safe stop while you are still able to control the brakes.

9. 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.

10. A vehicle equipped with an Anti-Lock Braking System (ABS) uses a ____ light to warn that the system is not working properly.
Green
Yellow
Orange
White

Anti-Lock Braking System (ABS) malfunction lamps are usually yellow. Even if the ABS isn't working properly, a driver will still have access to the vehicle's usual braking functions.

11. A tank endorsement is:
Only required when transporting gases.
Only required when transporting liquids.
Required when transporting both liquids and gases.
Optional when transporting hazardous materials.

With some exceptions, you must have a tank endorsement to transport liquids or gases. This applies to both hazardous and non-hazardous substances.

12. Both systems in a dual air brake systems share:
Air tanks.
Hoses.
Air lines.
An air compressor.

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

13. In a dual air brake system, a leak in one system:
Always means there are leaks in both systems.
May not affect the other system.
Is not something to worry about.
Will also affect the other system.

A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.

14. The ____ tells a driver how much pressure is in the air tanks.
Application pressure gauge
Air compressor governor
Supply pressure gauge
Drum brake

A vehicle that is equipped with air brakes must also be equipped with a supply pressure gauge. This gauge tells the driver how much air pressure is in each of the vehicle's air tanks.

15. Where is the safety relief valve usually located?
Near the rear brake
Near the front brake
In an air tank
On the dashboard

An air brake system's safety relief valve is located in the tank that is first to receive air from the compressor.

16. What should happen if the air pressure in the air brake system tanks falls below 60 psi?
A warning light should come on.
Lights should flash on the outside of the vehicle.
A message should appear on the control panel.
The vehicle should stop.

On vehicles with air brakes, a low air pressure warning signal will come on if the pressure in the air tanks falls below 60 psi. On large buses, the signal may activate at 80 to 85 psi.

17. An Anti-Lock Braking System (ABS):
Cannot be used with air brakes.
Should be used on dry pavement.
Can assist in maintaining control when braking.
Should only be used if all axles have ABS.

Anti-Lock Braking Systems (ABS) are compatible with air braking systems. ABS helps maintain control of a vehicle and prevents the wheels from locking up during hard braking on slippery surfaces. ABS can still provide benefits even if is present on only one axle.

18. If a vehicle has air brakes, the air compressor drive belt should be checked before each drive. In what condition should the belt be?
Loose
Tight
Cracked
Bumpy

When inspecting a vehicle with air brakes that has a belt-driven air compressor, you should check the condition and tightness of the belt. It should be in good condition.

19. Air tank drains:
Allow rain water to enter the tank.
Are used to drain water and compressor oil from the air tank.
Should never be opened.
Must remain open during transit.

In an air brake system, the air storage tanks must be drained to remove accumulated water and compressor oil. Failing to do so can cause damage. Manually operated drains should be used at the end of each day of driving.

20. The air storage tanks:
Hold only enough air for one braking cycle.
Hold enough air for brakes to be used several times if the compressor stops working.
Do not hold air unless there is an emergency.
Hold enough air for more than 1,000 braking cycles.

In an air brake system, the air storage tanks hold enough air for brakes to be used several times if the compressor stops working.

21. The air compressor governor controls:
When the air compressor pumps air into the air storage tanks.
How fast air is pumped into the air storage tanks.
The temperature of air pumped into the air storage tanks.
The speed of the vehicle.

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

22. Brake fade is a result of:
Exposure to sunlight.
Exposure to moisture.
Excessive use.
Not using the brakes enough.

If brakes are used too much, they will overheat and become less effective. This is referred to as brake fade.

23. Most heavy-duty vehicles use:
Mono air brake systems.
Dual air brake systems.
Triple air brake systems.
Quadruple air brake systems.

Most heavy-duty vehicles use dual air brake systems. A dual system has two separate air brake systems with a single set of controls.

24. To inspect slack adjusters on S-cam brakes, you need to:
Park on a hill and test the brakes.
Put on gloves and push in the slack adjusters.
Remove the drum and look inside.
Chock the wheels and disengage the parking brake.

Check each slack adjuster after parking on level ground, setting wheel chocks, and disengaging the parking brake. Pull the slack adjusters to make sure they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

25. The brake pedal is part of which braking system?
The service brake system
The parking brake system
The emergency brake system
The auxiliary brake system

The service brake system applies and releases the brakes when a driver presses the brake pedal while driving normally.

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