I rebuilt a WS several years ago; from what I remember, the seat is integral to the hydraulic block and not replaceable. Seats can be lapped - you can buy lapping tools that are essentially a diamond grit embedded ball on the end of a stick. I made one using a ball bearing epoxied to a stick...
Any progress on this? I'm wondering if 8-3 on the pump rod is compromised and 8-4 is taking the full force from the main cylinder. Does the jack actually lift weight, or does the seal blow out as soon as the lift arm encounters the load?
I don't know that there's much demand for that machine as designed, but fitted with a t slotted table, I think that would make a very nice drill press, given the tilt functionality.
Umm... I think the pump always sees cylinder pressure on a downstroke.
I'll 2nd that emotion - it sounds like he's essentially pumping against a brick wall.
It wasn't a must have until this year; we just had a string of 100 deg days, cooler today, but 5 days of 100+ coming up. I bought one of these last night: https://www.lowes.com/pd/MasterCool-2000-sq-ft-Window-Evaporative-Cooler-4000-CFM/50342060