Brother, I thought I had the only 1 left in existence! Good luck with the manual- I'm looking for the same thing! Just rebuilt ours, & the guy who took it apart doesn't 'remember' what went where!
The cup seals are basic for the ram & low pressure(3 1/2" & 1 1/4"?), the 11/16" cup seal can be bought at Allegheny York, the only supplier I could find. I ended up making 1 out of a slug of 60D buna N I had in about 20 mins. Made the wipers under the retaining caps out of a 1/4" thick urethane sheet with a gasket cutter-just be careful on the sizes-you need it to compress to function right. Make the diameters snug. McMAster Carr haas all you need.
Problem is, after re-assembly with the guy who took it apart, it'll pump up to 2000 psi & lock up. Probably drain it & take it back apart in the next few days, as time permits, to fogure out what goes where. In the meantime, if you find a hydraulic schematic let me know! Thx