UST Power System Model 1110c will not build pressure beyond 50psi
UST Power System Compressor (Photo: http://www.pepboys.com)
UST Power System Model 1110c. Was working a couple weeks ago and built up pressure to 100psi. Today, it would only go to 40psi.
I disassembled the cylinder head and cleaned the flapper valves and checked they were seating correctly.
Slight increase in pressure to 50psi, but no more.
My suspicions are now leading to the piston rings. If I can find parts for this, the rings would be the next thing I would do.
But trying to find any online support eludes me at this point.
Brian, I have uploaded a photo of a UST Power System compressor, though I cannot find an image of your specific model.
If yours is similar to this, then it has an oil fill tube and a vent. If your piston seals are leaking sufficiently that your compressor will not build pressure past 40 PSI, then you should be able to feel quite a flow of air out of the oil fill tube, as that cap is vented.
I rather more suspect that you have a gasket that lets go at 40 PSI. That you disassembled and reassembled the pump made a change. Maybe you torqued the bolts down tighter, but you managed to hold off the leaking of the gasket, if that is what it is, for another 10 PSI.
Try a high heat gasket sealer and see if that makes a difference, or make a new gasket from high heat gasketing material.
Also, empty the tank, remove, clean and replace the tank check valve.