Cheers Phil,

I've found some o rings but have a choice of 90 hardness or 70?
They are nitrile o rings, which hardness would you recommend?

They are slightly smaller inner diameter and a little thicker which I believe will be beneficial as the orings I got from chambers 0r066 seem to be to lose fitting and presumably why my ram won't hold pressure.

Many thanks for every ones help.

James