MEXICOWANDERER wrote:
I can state FOR A FACT that sulfur is a major contaminant and destroyer of natural and synthetic rubber and nitrile.
Carefully remove the o-ring seal.
You are going to need a splotch of tire and tube patch cleaning liquid. Bad for the skin and anything else it touches. Use nitrile medical or mechanic gloves.
Use a rag. Wet the rag with fluid. Gently wipe around the o-ring several times with the tube tire patch cleaning compound. The rag contact area will turn pitch black. Don't slop this stuff on! But allow enough to wet the rubber. Use a wath or clock. One minute of wiping. You will have to re-wet the cloth to make it a full minute.
Wipe dry with a clean dry cloth.
Smear silicone dielectric grease around the o-ring. Allow it to "soak-in" for five minutes then gently wipe off excess but don't try to scrub off all the grease.
Reassemble. Check for leaks.
I did this on several Cummins 855 PT injector pumps. The process is valid.
Nothing seems to substitute for tire tube patch cleaner. It definitely swells the rubber slightly. No leaks in 7-years following repairs to my own bus PT pump.
While search the net on this pump came across a lot of reference to the PT pump. I assume this is not what I have.
Does the PT pump have an access plate like this?
I will follow your procedure if I cannot locate a new o-ring.
