Originally Posted by musigenesis
Air pressure should be around 120. You will (should) hear a beeping if the pressure drops below 60; you'll also see a swinging red warning arm come out top middle of the windshield. If this happens while driving, get off to the side ASAP because your brakes are about to lock up. If you hear this beeping on startup (and assuming the pressure comes up to 120 in a few minutes) it means the bus hasn't been run in awhile and all the residual pressure has leaked out.
So what if the pressure did leak out... will it build up again and be good to go?
In the has t been started in awhile scenario...
Got it if my air breaks lock up. Pull over.