Quote Originally Posted by slow_runner View Post
More help needed thanks.
Despite being stripped down, cleaned, then carefully reassembled, the pump will only attain 150bar.
All manner of O ring grades have been tried to no avail. So now we are back to original spec with no change in behaviour of the pump.
Would we be correct in assuming that 150bar is the 2nd stage limit and the problem could exist somewhere in the final stage? But where, why?
Has anyone had similar results and what was the solution?

It is driving Jeff crazy; I'm Ok as I am there already
I would check the final stage seal. This is the one most people substitute out for a cheaper commonly available o ring, needs to be the original PU spec; nitrile and viton dont cut it.