PSI's
Maintenance and Inspections
Components
Miscellaneous
Brakes
100

At what pressure is the governor cut in?

100 PSI

100

How often should you drain your air tanks?

Daily

100

What does the air compressor do?

Pumps air into the storage tanks

100

What is an application pressure guage?

Shows how much pressure you are applying to the service brake

100

What are foundation brakes?

Brakes used at each wheel
200

At what pressure is the governor cut out?

125 PSI

200

How do you test the low pressure warning?

Fan the brakes down to 60 PSI

200

What does the air compressor governor do?

Controls when the compressor will pump air inot the storage tanks

200

What is the difference in the parking and emergency brake?

Parking brakes are set by the driver using the controls in the cab. Emergency brakes automatically apply in the event of pressure loss

200

What is the most common foundation brake?

S-Cam

300

What pressure does the low pressure warning come on?

60 PSI

300

How do you test the emergency brakes?

Fan the brake down to 20-45 PSI

300

What two things are required on a vehicle with air brakes?

Low pressure warning

Supply gauge

300

What is the stop light switch and what controls it?

Electric switch controlled by air pressure that causes the brake lights to light up when the brake pedal is pushed

300

What is the service brake?

Foot pedal

400

At what pressure do the emergency brake set?

20-45 PSI

400

How do you test the spring brakes?

With the spring brakes set, put the vehicle in a low gear and pull forward against them. It should not move 

400

What keeps air in the system should the compressor develop a leak?

One way check valve

400

What is a wig-wag?

Low air pressure warning formerly used on buses

400

What is the maximum pressure loss in one minute in a single vehicle with the spring brakes released?

2 PSI

500

At what pressure does the safety valve release?

150 PSI

500

Explain how to check slack adjusters

Park on level ground, chock the wheels, release the brakes, pull on each slack adjuster, should not move more than one inch

500

What keeps air in the system should the trailer break away or develop a bad leak?

Tractor protection valve

500

What is a dual parking brake control?

Used to move the vehicle a short distance in the event of an emergency

500

What is brake fade?

Applying the brakes harder and harder to get the same stopping power

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