District of Columbia CDL Air Brakes 2 - DMV Written Test Questions with Answers - MCQGeeks.com

Q.1

Most heavy-duty vehicles use:

Single air brake systems.
Dual air brake systems.
Triple air brake systems.
Quadruple air brake systems.

Q.2

Failing to drain the tanks in an air brake system can result in:

Water freezing and causing brake failure.
Squishy brakes.
Too much air collecting.
Too much fuel being carried.

Q.3

To ensure normal stopping power, drivers of vehicles equipped with a front brake limiting valve should:

Set the control to normal.
Set the control to the off position.
Set the control to neutral.
Keep the control at the halfway mark.

Q.4

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

Q.5

What kind of force must emergency brakes use?

Air pressure
Mechanical
Heavy
Electrical

Q.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.

Q.7

While driving, spring brakes are generally held in place by:

Air pressure.
Chocks.
Foundation brakes.
Sturdy ties.

Q.8

How is water and compressor oil removed from the bottom of an air storage tank?

The water and oil are siphoned out of the tank.
A drain valve is opened to remove the water and oil from the tank.
The water and oil are removed automatically as the brakes are used.
A sponge is used to soak up the water and oil.

Q.9

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

Q.10

When the brake pedal is depressed, air brakes work:

Immediately.
After a short delay.
After about a minute.
Only if the green lever on the control panel is pushed down.

Q.11

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.

Q.12

What can happen if a parking brake is used in very wet weather when temperatures are below freezing?

The brakes will squeak.
The brakes may freeze so the vehicle cannot move.
The brakes may suddenly release by themselves.
The brakes may explode.

Q.13

When about to drive a vehicle with a dual brake system, a driver should:

Let the vehicle warm up to ensure the fuel reaches the engine.
Wait for air pressure to build in both the primary and secondary systems.
Begin driving just after the engine starts.
Pump the pedal about 20 times to build pressure, then begin driving.

Q.14

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.

Q.15

Emergency brakes are:

Not required on trucks.
Only required on trailers.
Required on tractors.
Only required when transporting hazardous materials.

Q.16

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.

Q.17

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

Q.18

In a dual air brake system:

Air tanks are shared by both systems.
Each system has its own air tanks.
You must designate which system you are using.
Brakes on only one side of the vehicle will work.

Q.19

Emergency brakes:

Are not required on trucks.
Are only required on trailers.
Are required on tractors.
Are optional.

Q.20

Spring brakes come on:

When too much air pressure is lost.
When a control on the dashboard is activated.
When the tires have minimal tread depth.
When the brakes are noisy.

Q.21

Some air brake systems use alcohol:

To reduce the risk of ice forming in air brake valves.
To make the compressor run more efficiently.
To lubricate parts of the braking system.
To reduce the risk of rust forming on air brake valves.

Q.22

To stop in a vehicle that uses air brakes, the driver should:

Pull the air brake lever.
Engage the brake lever.
Push the brake pedal down.
Pull the brake pedal up.

Q.23

You should not use the parking brake:

If your vehicle is stopped on a level surface.
If your vehicle is stopped on a slight incline.
If your vehicle's brakes are very hot.
If your vehicle's other braking systems seem to be working adequately.

Q.24

Test the low pressure warning signal:

Once a month.
Once a week.
Twice a week.
Before every trip.

Q.25

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.

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