Hi-I am involved in an on going discussion with others about the use of o-ring grease when mounting proportional valves, stack valves on subplates, etc,. What is the general rule when mounting valves and the use of o-ring grease. The Vickers valve rebuild guy says he will not guarantee a valve that 0-ring grease has been used. Whats the deal? What is the proper lubrication of 0-rings? Thanks, Brett

Googled

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o-ring material

marcorubber

Obviously a lot of O-ring material to choose from.....Generally looks like it should not be any problems with stricly petroleum based grease and non-silicone based orings like Buna-N and Viton....watch out for all the additives in grease though....

Very interesting chart, this MarcoRubber, with some great info...

Thanks Akkamaan, the particular grease I have used is Dow-Corning 55 o-ring lube,mainly for pneumatics. Does not say anything about hydraulics-Brett p.s. will check out the site you suggested-

Grease is a contaminant and most major manufacturers don't use it unless necessary. If you have a correct o-ring size, lubricating with the fluid to be used is just fine. I don't think there is a difficulty in putting valve o-ring using the system hydraulic oil.

May the Lord take care of Bud T... Thanks Bud T for your very nice effort to help...

Bret I believe the concern your vickers valve rebuild guy has is grease trapped in a face seal application can potentially cause an extrusion gap for the oring to extrude into or the grease will work it's way out leaving your fasteners under torqued. It happens more commonly with greased, gasketed interfaces, but the argument is still the same.

I only 'lightly' grease orings in a face sealing application if I'm worried about them dropping out during installation. I realize they make glue for such concerns, but I just can't bring myself to do it.

Reciprocating, revolving or static orings that are squezing into a bore or over a shaft get oil. I also oil orings sealing ORFS and ORB fittings so they don't gall or tear during assembly. Definitely don't impact ORB fittings in unless they are already snugged up as they can gall and tear.

I would put more concern into knowing when to use 70 durometer and 90 durometer orings.