muddstopper
Veteran Member
That is correct, some of the pumps wont shift to high pressure until 600psi, but it all depends on where they are set. If your cylinder is bad, it could be bypassing enough to prevent high pressure build up, but it would have to be bypassing pretty bad. To be sure, unhook a hose from the cylinder and cap it off and then try deadheading the pump. If it still wont develop more than 900psi, and the relief is adjusted all the way to max pressure, then you can start looking for a pump. If after testing by capping the hose, your machine does make max pressure, its time for a cyl rebuild.