this is all great advice ...as I am a only tech on a small island in the Caribbean I have to try the simpler stuff first before going down the route of pulling jacks from casings although I am beginning to think it is the check valve. It has just come back after two weeks of ok running. Pete, that is what is happening...it looks like the bottom stage of the left jack is 'hanging up' . I am going back today and I will try a manual resynch with no springs or with the bolts removed in case they are bottoming out as suggested.
anybody had any experience pulling these jacks or have any literature showing part numbers and what I will find when I do would be very helpful. thanks again guys .
