Air Brakes 3

In which of the following situations should you not apply the parking brakes?

• If the brakes are very hot

• When you were testing whether they will hold the vehicle

• If you’re parking for less than one hour

Excessive heat caused by overuse of the service brakes can cause

• Modulating control valve to wear out.

• The brakes to fade.

• The brake line needs to split

When you put hard on a slack adjuster, if it has more than ______ a free play, the slack adjuster may need adjustment.

• 1/2 inch

• 1/4 inch

• 1 inch

A typical air brake system is fully charged at

• 75 psi

• 150 psi

• 125 psi

If you do not have an automatic tank drain, When should you drain your air tanks?

• After every four hours of service

• At the end of each working day

• Once a week

To apply the parking brakes under normal conditions,

• Let the air out of the brake chambers.

• Be sure the air brake system is fully pressurized.

• Turn off the engine.

Air braking takes more time than hydraulic braking because air

• Brakes use different brake drums.

• Brakes require heavier return springs.

• Takes more time to flow through lines then hydraulic fluid

When you apply the brake pedal, the brake shoes and linings are pressed against the

• Brake drum.

• Slack adjuster.

• S-cam.

During normal driving, spring brakes are usually held back by

• Air pressure.

• Springs.

• Bolts and braces.

What is the first thing you should do if the low air pressure warning comes on?

• Upshift.

• Downshift.

• Stop.