Originally Posted by frank-id
It would seem the govenor is fussy or tired. If this control is exposed to water, the unloader valve will stick closed. It acts as tho the compressor will pump up till the pressure relief valve opens. Go get a rebuild control for about $35. If possible, try a govenor from another bus. Most govenors are preset to about 120 PSI. The govenor controls the compressor valves. Some truck/bus drivers turn up thebrake system's pressure in an attempt to make the brakes perform better. This does not improve braking. Braking is only improved by adjusting the slack adjustera at each wheel. Fraqnk
I removed the governor from the compressor and took it apart on the bench, removed the dust cap in the adjuster end, I removed the snap ring that retains the adjuster assembly and piston, after removing the adjuster and spring assembly I found some, clean, old oil that, was kinda sticky like it had varnished, I cleaned that out with my finger and a rag then sprayed some PB Blaster air tool oil into the bore as a lube and tapped the body in my hand until the piston made its way to the open end and I could pull it out with my fingers, once out the O rings looked a little worn, more square than worn but still looked to be in good shape, the springs on the internal valve with in the piston body itself seem to work ok, I sprayed the whole assembly with the PB blaster air tool oil to clean it up, the bore and body of the governor, I sprayed it out good with carb cleaner and compressed air then lubed it again with the PB Blaster air tool oil and assembled the valve, it seem to slide in ok nothing rough or real loose.
I guess tomorrow I will remove the governor again and look closer at the small springs in the piston that are some sort of a valve (not 100% sure how this part works yet need a schematic) to ensure none are broken, I think that assembly sends a signal to the dryer to purge off any water and oil? I will also at this time replace the two O rings on the piston.
Thanks again for the help, any other thoughts?