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Kansas CDL DMV Air Brakes 1

Take 6 practice tests for CDL is the best way to prepare for your Kansas DMV exam is by taking our free practice tests. The following question are from real Kansas 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. Vehicles with dual air brake systems:
Maintain full-capacity air pressure in the braking systems even when the vehicle is not running.
Maintain some air pressure in the braking systems when the vehicle is not running.
Must be run to build enough air pressure to brakes to operate properly.
Do not need time to build air pressure before a trip.

Before driving a vehicle with a dual air brake system, you must allow the air compressor time to build up at least 100 psi of air pressure in both the primary and secondary systems.

2. While driving downhill, you should brake until you reach a speed that is ____ below your safe speed, then release the brake pedal.
5 mph
10 mph
15 mph
20 mph

While driving downhill, you should hold down the brake pedal until your vehicle reaches a speed 5 mph below your safe speed, then release the brake pedal. Repeat this process.

3. The air pressure in a dual air brake system should build from 85 to 100 psi within:
Two minutes.
15 seconds.
10 minutes.
45 seconds.

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.

4. When traveling down a steep downgrade:
The air brakes should be used.
Shift into a lower gear, then use brakes to supplement the braking effect of the engine.
The vehicle should be continually downshifted in the place of using the brakes.
The vehicle should be driven on the shoulder.

On a downgrade, the braking effect of the engine should be your primary method of controlling speed. Shift down to a lower gear before starting down the hill and save the brakes for additional slowing or stopping that may be required by road or traffic conditions.

5. How is the parking brake released?
By tapping on the brake pedal three times
By pushing in the brake control knob
By engaging the accelerator
By tapping the accelerator twice

In newer vehicles with air brakes, the parking brakes are controlled by a diamond-shaped yellow knob. Pull the knob out to activate the parking brakes and push it in to release them.

6. During an applied leakage test, the maximum leakage rate for a triple combination vehicle is:
10 psi in a minute.
8 psi in a minute.
6 psi in a minute.
4 psi in a minute.

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.

7. 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.

8. 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.

9. A modulating control valve can control the:
Spring brakes.
Landing gear.
Air brakes.
Anti-lock braking system (ABS).

A modulating control valve allows a driver to gradually apply spring brakes. In equipped vehicles, the valve is controlled by a lever located on the dashboard.

10. 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.

11. What do anti-lock brakes do?
Help a driver avoid wheel lockup
Lock up the front wheels
Prevent a vehicle from accelerating while traveling uphill
Prevent a vehicle from accelerating while traveling downhill

The function of an Anti-Lock Braking System (ABS) is to prevent the vehicle's wheels from locking up from hard brake application.

12. On trucks and buses, where are ABS malfunction lamps located?
On the driver’s door
On the instrument panel
On the outside of the vehicle by the passenger’s door
Under the hood

Tractors, trucks, and buses with Anti-Lock Braking Systems (ABS) have yellow malfunction lamps located on their instrument panels. Trailers have yellow ABS malfunction lamps on their left side, either on the front or rear corner.

13. 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.

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

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

15. Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:
Air pressure falls below 45 psi.
Air pressure falls below 20 psi.
Driving downhill.
Driving uphill.

Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.

16. What is a wig wag?
A type of warning system
A tube used to move air from the compressor to the tanks
A noise made by air brakes when used
A part within the braking unit that allows air to move freely

A wig wag is a type of low air pressure warning device in an air brake system. It drops a mechanical arm into the driver's view when the air pressure in the tanks falls below 60 psi.

17. Before starting down a hill, be sure to:
Accelerate.
Switch into a high gear.
Sound your horn.
Switch into a low gear.

Before starting down a hill, be sure to switch into a low gear. Gravity will increase your vehicle's speed as you travel downhill.

18. A dual air brake system:
Has a single air brake system, but uses two sets of controls.
Has one air brake system for each side of the truck.
Has two brakes for each wheel.
Has two separate air brake systems, but uses a single set of controls.

A dual air brake system has two separate air brake systems that use a single set of brake controls. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle.

19. Front brake limiting valves were intended to:
Prevent the front tires from skidding.
Prevent the front tires from overheating.
Create equal brake usage.
Remove uncertainty when applying the brakes.

Some older vehicles with air brakes have front brake limiting valves. These valves were intended to reduce the risk of front wheels skidding. However, research has shown that such devices are unnecessary, so they should be left in the "normal" position.

20. Test the low pressure warning signal:
Once a month.
Once a week.
Twice a week.
Before every trip.

It is essential that your low pressure warning light function 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.

21. 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.

22. Most heavy-duty vehicles use:
Single air brake systems.
Dual air brake systems.
Triple air brake systems.
Quadruple air brake systems.

Most heavy-duty vehicles use dual air brake systems, in which there are two separate braking systems operated by a single set of controls. Each system operates the brakes on different axles.

23. 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.

24. Which of the following is not a part of an air brake system?
A service brake system
A parking brake system
An emergency brake system
An axle brake system

Air brakes consists of three separate braking systems: the service brake system, the parking brake system, and the emergency brake system.

25. If the spring brakes are activated, you should never:
Push down the brake pedal.
Open the hood.
Release air from the air storage tanks.
Open the door to the cab.

Never apply the brake pedal if your spring breaks are activated. Brakes can be damaged if they are subject to both springs and air pressure.

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