UniDrive Test

What are air dryers designed to do?

Sends information to the dashboard gauges
Pushed the air through the air hoses
Removes contamination from the air pressure being delivered by the air compressor
It dries the air

How long does it take the compressor to build 50 to 90 PSI after running the engine at 1200 rpm?

15 minutes
10 minutes
5 minutes
3 minutes

What's the purpose of safety valves?

Allows the brake hoses to be replaced easily
Allows the cylinders to be cleaned
Protects the system from being over-pressurized
Just a safety thing

What controls the compressor as needed to maintain air pressor?

The president
The premier
The governor
The senator

After the air compressor pressurizes the air, where does it pump it to?

To one trailer at a time
The left side brakes first
The storage tanks
Directly to the tractor brakes

Which statement is incorrect? Air brakes are different because...

The require more driver involvement to make sure that the system is operating safely
There are less gauges and controls
Vehicle reaction is different
The pedals feel different

What is a lanyard pull cable used for?

The open the drain valves
To secure the air hoses to the tank
To attach the drain valves to the tank
To tighten the air hoses

How often should you drain the supply tanks?

Never
Only if the gauges show a problem
During pre-trip inspections, enroute inspections and fueling
Once you notice contamination

Should the air tanks be drained before doing any air system work?

Only when close to the compressor
If near the coupler
No
yes

If there is a small air leak, how does the air brake system adjust on the fly?

The other brakes take up the slack
It takes longer to stop the vehicle
No adjustments are taken
The compressors pump in more air

What does the supply circuit do?

Compresses and cleans the air, maintains consistent air pressure
Provides information for the employer to use for training
None of the above
Adjust the tire pressure

Where is the driver when control and quick release valves exhaust forcefully?

Outside the vehicle
Inside the cab
Under the hood
Doing routine maintenance

Where are drain valves located?

On the top of air pressure tanks
At the top right of the air pressure tank
Under all air pressure tanks
At the top left of air pressure tanks

Which statement is false? The supply tank functions:

Distributes to the two service tanks
Tends to be a larger tank
It's the first tank that receives air pressure from the compressor
It collects contamination not captured by the air dryer

What's another name for an air pressure purge?

Dryer
Flow
Back-flush
Joint

Do you need to wear any personal protective equipment when servicing air system work?

Yes
When releasing the air system
Only if close to the engine
None of the above

Whose responsibility is it to ensure the air brakes are working properly?

The driver
The employer
The maintenance team
The industry inspector

Which is not a reason for slow air pressure build-up?

Excessive system leakage
A faulty or worn compressor
Plugged intake
Too much idling

An Original Equipment Manufacturer (OEM) may use kilopascals (kPa). What does this measure?

Vehicle weight
None of the above
Air pressure
Trailer weight

What do Inline Alcohol Injectors do?

Cleans the air hoses
Helps to fill the compressors
Polishes the compressors
Adds vaporized air line antifreeze to the air supply

What is the standard way to measure air pressure?

Inches
Using Pounds Per Square Inch (PSI)
Square footage
Litres per inch

What is the definition of compressed air with regard to air brakes?

It's just air
A small amount of air placed in a larger tanks
Specially treated air
Compressed air that is pressed into a smaller space

Which statement is false? Air brakes are different because...

There are more gauges and controls
Vehicle reaction feels different
The pedals feel different
They require less driver involvement

How do you monitor the air pressure?

Testing the brakes on occasion
You have to manually check the tanks
None of the above
Gauges on the dashboard

Which braking system creates greater power?

Air brakes
Mechanical brakes
They're all the same
Hydraulic brakes

When does contamination drain most effectively?

Once more air is forced through the system
After the tanks are empty
It doesn't
Once the park brakes are applied

The air compressor is directly driven from where?

The internal gearing of the engine
A separate generator
A separate pump
Fan belts

At what point does the governor cut out?

110-125 psi
It doesn't
130-145 psi
120-135 psi

What is another name that the supply tank is called?

The purge tank
The main tank
The air tank
None of the above

At what point does the governor cut in?

20-25 psi
10-15 psi
40-45 psi
30-35 psi

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