Keyword: (ALSAPS) I have this saved as a document. I don't know how to
remove that frown on #4.
1.(A)ir leakage test,
2.(L)ow air pressure warning signal test
3.(S)pring brake test,
4:(A)ir compressor cut off test
5.(P)arking brake test.
6.(S)ervice brake test.
1. Air leakage: They are going to ask you to get behind the wheel for this test. The bus will be off, and must be off for 1-3. To do the air leakage rate you look at the air pressure gauge. Tell the instructor how much air is in the gauge. You then depress the brake pedal. This gives you your initial air loss. Tell the instructor this, immediately. You keep your foot on the brake pedal for two minutes, to get the air leakage rate. So it's like 3 parts for #1.
*example is when you get behind the wheel and read the gauge it says 120lbs of air. You say I have 120lbs of air. You step on the brake pedal, and it immediately drops to 115lbs psi, you say "it's at 115psi my initial air loss is 5lbs psi". You then keep your foot on the brake pedal for 2 minutes (alot don't let you wait that long), and you should lose no more that 2lbs per minute. If it goes down to 113lbs, you say "it's at 113lbs psi, my air leakage rate is 2lbs psi in 2 minutes*.
2. Low Air Buzzer: You turn the control knob to lights, but don't start the engine. You pump the brake pedal until the buzzer goes off. When you hear it you tell the instructor at what PSI did it go off. That should be at around 80-60PSI.
3. Spring brake: You make sure the bus is on level ground, release the parking brake (aka spring brake), and continue depressing the brake pedal. The parking brake should pop up at around 40-30 psi. When it pops up, you tell the instructor "spring brakes engaged at whatever it is, PSI".
4. Air Compressor: Now you turn on the bus, and let it run (with fast idle on). (They may make you do a wrap around during this time (pointing things out in front that should be there and not broken)). Pay attention to the PSSSHHHHH sound. That would be the compressor cutting off, and that should be at 120-130lbs psi in the RTS they train everyone on. Tell the instructor "the compressor cut out at whatever it is, PSI".
5. Parking Brake: With bus still running you shut off the fast idle, and then put the bus in drive (DO NOT RELEASE THE PARKING BRAKES). You give the bus a little gas, and the bus should lean to the right (door side), but not move. Say "bus leaned to the right, bus didn't move, parking brakes work properly".
6. Service Brakes: You now disengage the parking brakes, and let the bus roll 20-40ft (do it length of bus to be safe....40ft). Press the brake pedal, and bus should stop without pulling to the left or to the right. Say "bus stopped normally, no pulling to the left or right. That means the brakes are aligned properly.