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Colorado CDL DMV Air Brakes 1

Take 6 practice tests for CDL is the best way to prepare for your Colorado DMV exam is by taking our free practice tests. The following question are from real Colorado 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. While driving, spring brakes are generally held in place by:
Air pressure.
Chocks.
Foundation brakes.
Sturdy ties.

While driving, spring brakes are generally held in place by air pressure. If the air pressure gets low enough, the springs will activate the brakes.

2. 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 3,000 miles

To prevent the build up of oil and water in a vehicle's air tanks, manually operated air tank drains should be used at the end of each day of driving.

3. 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.

4. Emergency brakes:
Are not required on trucks.
Are only required on trailers.
Are required on tractors.
Are optional.

All trucks, truck tractors, and buses must be equipped with emergency brakes and parking brakes. These brakes must be held by mechanical force.

5. What color are ABS malfunction lamps?
Orange
Yellow
Green
Blue

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

6. 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.

7. When inspecting your brakes, a slack adjuster should move ____ from where it is attached to the push rod.
At least three inches
More than two inches
Up to five inches
No more than one inch

Check each slack adjuster after 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.

8. During a static leakage test, the maximum leakage rate for a triple combination vehicle with air brakes is ____ in a minute.
3 psi
5 psi
7 psi
9 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 air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

9. Applying the brake pedal causes air pressure to activate an electric switch and:
Turn off the brake lights.
Turn on the low pressure warning light.
Turn on the brake lights.
Turn off the low pressure warning light.

In a vehicle with air brakes, the brake lights are activated when the brake pedal is pushed and air pressure moves an electric switch. With the application of air pressure, the switch will then turn on the brake lights.

10. Braking mechanisms are located ____ a brake drum.
Outside
Inside
Next to
On top of

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.

11. 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.

12. How should you test the low pressure warning signal?
Engage and disable the parking brake.
Rapidly press and release the brake pedal.
Open the rear shut-off valves.
Uncouple and recouple all glad hands.

It is essential that your low pressure warning light functions properly. After allowing the system to charge, you can test the warning signal by rapidly applying and releasing the brake pedal. This will release air from the braking system and the warning signal should come on when pressure drops to a dangerous level.

13. What happens if the air pressure in a system's air tanks falls below 60 psi?
A warning light will come on.
The vehicle will not shift out of gear.
The front lights will flash.
The vehicle should stop.

In an air brake system, a low pressure warning signal should activate if the pressure in the air tanks falls to a level below 60 psi. This signal may be in the form of a warning light or a wig wag.

14. When you need to stop in an emergency, you should:
Lock the wheels and skid to a stop.
Stop in a way that keeps your vehicle in a straight line.
Stop in a way that turns your vehicle.
Expect your vehicle to slow down more quickly than usual.

If you need to make an emergency stop, you can use either the controlled braking method or the stab braking method. It's important to brake in a way that keeps your vehicle traveling in a straight line while still allowing you to turn, if necessary.

15. 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.

16. How many air storage tanks are used in an air brake system?
Two tanks
Four tanks
Six tanks
The number varies.

Air storage tanks are used to hold compressed air. The number and size of air tanks in an air brake system varies among vehicles.

17. What does ABS do?
Prevent wheel lockup
Prevent the air compressor from overheating
Prevent the front brakes from being used on ice
Prevent the brakes from being used if downshifting would be more effective

The purpose of an Anti-Lock Braking System (ABS) is to prevent wheels from locking up during hard applications of the brakes, especially on slippery surfaces.

18. Brakes may get out of adjustment:
If they are too hot.
In colder weather.
If they are used.
If they get wet.

Brakes can get out of adjustment quickly, especially if they are used to the point of overheating. Brake adjustment should be checked frequently.

19. When using the controlled braking method in an emergency situation, you should:
Apply the brakes as hard as possible without locking the wheels.
Apply the brakes with about half of your usual force.
Apply the brakes so the wheels lock.
Apply the brakes with minimal pressure.

The controlled braking method for emergency stops involves applying the brakes as hard as you can without locking the wheels. Keep steering wheel movements small when braking in this way.

20. Which type of brakes do most heavy-duty vehicles have?
Air brakes
Solid brakes
Liquid brakes
Gravity brakes

For safety, most heavy-duty vehicles are equipped with dual air brake systems.

21. The emergency brake system uses:
Only parts of the parking brake system.
Only parts of the service brake system.
Parts of both the parking and service brake systems.
Only parts unique to the emergency brake system.

In an air brake system, there are three different braking systems: a service brake system, a parking brake system, and an emergency brake system. The emergency brake system uses parts of both the parking and service brake systems.

22. 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.

23. The application pressure gauge:
Shows how much air pressure is being applied to the brakes.
Shows the temperature of air being used in the braking system.
Shows the pressure of the air coming from the compressor.
Shows the number of times the brakes have been used.

In an air brake system, the application pressure gauge shows how much air pressure is being applied to the brakes. Not all vehicles with an air brake system have this gauge.

24. When only the tractor is equipped with an Anti-Lock Braking System (ABS):
There is a decreased risk of jackknifing.
There is an increased risk of jackknifing.
The brakes will not work as effectively as they would without ABS.
The brakes will become more sensitive.

If a tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the risk of jackknifing will be reduced and the driver should still be able to maintain steering control. If only the trailer is equipped with ABS, it is less likely that the trailer will swing out to one side.

25. When you press the brake pedal in a vehicle with S-cam brakes, air pressure pushes out the rod and moves the:
Slack adjuster.
Axle.
Brake drum.
Alcohol evaporator.

When pressing the brake pedal in a vehicle with S-cam brakes, air will enter the brake chambers. The added air pressure will push out the rods and move slack adjusters, twisting the brake camshafts.

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