UniDrive Test

What are cracked brake drums caused by?

Poor installation
Old brake drums
Poorly maintained brakes
A series of overheating and cooling

With regard to brake lining, what causes oil saturation?

None of the above
Leaking wheel seals
Oil from the asphalt
Leaking couplers

What happens when the clevis completely separates?

The brakes begin to squeal
The brakes lose power and takes a longer distance to stop the vehicle
The brakes can lock
The brakes cease to work when the clevis completely separates

When does a loose air tank cause a failure?

It doesn't
When it separates from the circuit it supplies
None of the above
When the psi drop below 20 psi

What causes the cracks in the brake drums to widen, and eventually the drum comes apart?

Lack of lubricant
Braking hard too often
Centrifugal force on the separated sections
When the brakes are pumped too often

If there are system failures that affect braking ability, what needs to happen?

The vehicle must be placed out-of-service until appropriate repairs are made
Call your employer and ask for direction
Brake much sooner so a safe stop can be made
Drive at a slower speed

What would you have to do to confirm that the brake chamber is securely installed?

Inspect the mounting fasteners and brackets
None of the above
Test the brakes
Look on the ground for any loose pieces

What causes chaffed air lines?

Defective couplers
Too much air being pushed through the lines
A defect in the air lines
Incorrectly secured air lines which rub on nearby parts

To check the governor, the cut out should be at what rpm?

70-85 psi
120-135 psi
150-170 psi
80-90 psi

What happens when there is brake lining failure?

Nothing
It decreases the friction surface area
Liquid oozes out of the brakes
It causes the brake pads to cease together

What causes the clevis pins to work their way out?

Poor adjustments
None of the above
When the cotter pin sheers
When too much air pressure goes through the lines

During a vehicle inspection, how do you confirm that the air tanks are securely mounted?

Take a look at the mounts
Listen for air leaks
Push each end
None of the above

The CVSA standards require at least how much lining thickness?

3/4 inch (19 mm)
3/8 inch (9.5 mm)
1/4 inch (7 mm)
1/2 inch (13 mm)

If there are any corrosion or damage seen in brake chambers or clamp rings, who is qualified to repair it?

It doesn't matter
Anyone on the maintenance team
The driver
Certified heavy equipment technicians

To check the air compressor, run the engine at 1200 rpm, the low-pressure warning should go out at what rpm?

120 rpm
60 rpm
80 rpm
100 rpm

To check the air compressor, run the engine at 1200 rpm, then start timing when the air pressure is at what rpm?

It doesn't matter
90 rpm
70 rpm
50 rpm

What causes hose bulges within the air lines?

Internal structure failure or excessive chaffing
Debris in the air lines
Too much air being pushed through the lines
Defective couplers

What is the maximum air pressure leakage allowable during the air systems leaks procedure?

5 psi loss per service circuit for power units
2 psi loss per service circuit for power units
3 psi loss per service circuit for power units
4 psi loss per service circuit for power units

Why should you not mix air line fittings?

Different systems of fittings are not compatible with each other
The brakes seize up
They fall off
The tractor won't respond well to the changes

Within the commercial vehicle industry, what does CVSA refer to?

Complimentary Vehicular Safety Act
Commercial Vehicle Safety Alliance
Commercial Vehicle Secondary Air
None of the above

What does the phrase cammed over refer to?

Missing brake linings
Excessively worn brake linings
None of the above
Thick brake linings

What does the system leaks procedure check for?

Leaks with the governor
Leaks with the air lines
Leaks with the air compressor
The entire air brake system for pressure leaks through one operation

What is the only air line not filled during this air systems leaks procedure?

None of the above
The lines to the park brake
The control line from the hand valve to the double check valve
The lines leading up to the compressor

Which of the following is not included in the air supply circuit inspection?

The governor
The low air pressure warning device
The air compressor
The air dryer

What is the major issue of a kinked air line?

It causes reductions in brake performance by restricting or blocking the flow of air pressure
None of the above
It stretches the air lines
It stretches the air lines

Can loose brake chambers still apply some application force to the foundation brakes?

Yes, depending on how loose they are
100%
Not at all
No one knows

What happens after a plastic air line is kinked?

It is permanently damaged and must be replaced
It shortens the hose
It takes time to unkink it
None of the above

To check the air compressor, run the engine at 1200 rpm and stop the timing when the air pressure is at what rpm?

90 psi
It doesn't matter as long as it's been running for six minutes
140 psi
120 psi

Air system failures are sometimes dealt with by blocking off the air lines that supply the failed component. Is this acceptable?

If driving at low speeds
Never
Only if directed by your employer
Yes, until you get back to the yard

What can foundation brake component failures can result in?

Anything from a minor application reduction to a complete failure
A lot of noise
A suspended driver's license
Demerit points

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