Dual air system, knowledge demonstration
What is the function of the air governor?
To regulate the air pressure.
During the static test, you detect an air leak. Where is it coming from?
The possible sources are: the compressor, air dryer, air governor, air tanks, air lines to service brake valve and/or parking brake valve.
During the applied test, you detect an air leak. Where is it coming from?
The service brake lines, and all brake chambers.
You are losing air in your rear tank. How do you stop?
Apply the service brake, the bus will come to a stop, utilizing the front brakes and modulated spring brakes in the rear.
You are losing air in your front tank. What will happen?
Low air warning will activate at all psi readings at 60, and below, using the service break the bus will be able to stop.
You were losing air in both tanks. What causes spring breaks to apply?
An absence of air.
When you release the air brake manually, where does the air go?
Into the spring brake chambers: compressing the springs together, and releasing the brakes.
What is the purpose of the single check valve?
It allows air to flow in one direction.
What is the purpose of the double check valve?
Protects the air supply in both tanks by shuttling air from tank to another.
What would happen if you had a catastrophic loss in both tanks?
The vehicle will come to stop by applying the spring breaks automatically. And bus will be unable to move. Only the mechanic will be able to fix this, not the tow truck: Newark be unable to move. Only the mechanic will be able to fix this, not the tow truck: nor can CHP authorized the further movement of the bus.
How do you activate the emergency stopping system on this bus. If he loss of error occurs in one air tank only, front or rear?
It is activated by use of the service brake pedal.
What would happen to the bus if all the air supply is lost at one time?
The buzzer will sound, and the spring breaks will apply to bring the bus into a stop.
What should you do with an air gauge indicates a major loss of air in one tank?
The bus will continue to run and should be stopped by use of the service brake pedal as soon as possible, in a safe place.
What is the best way to check to make sure the emergency warning devices are operating properly?
Drain the air tanks, one at a time and observe the air gauges to make sure the shuttle valve (two-way check, valve) is working and the buzzer works. If the rear tank is drained, the bus could be moved and the brake pedal used to stop the bus with front service brakes and rear spring breaks.
How is the parking brake tested?
Move the vehicle at a slow speed, 1 or 2 mph, and apply the parking brake control. Vehicle should stop abrupt.
What breaks (front or rear) are applied during emergency brake application?
Rear
When manually applying the parking brake control (emergency stopping system) at approximately 20 mph, if the bus continues with little, or no break affect, what is wrong?
Rear brakes are probably out of adjustment.