I finished up rebuilding my Galion Hoist today.
Heres all the pictures of the tear down and rebuild.The lid of the hydraulic cannister has a 2 3/4" nut that screws down over the arm, compressing 6 rings of packing material that seal the arm. I had to loosen it with a chisel but I made/cut a wrench out of 3/8" steel to reinstall. Theres one huge o-ring in the lid that seals up the area around it (6" x 6 1/4" x 1/8").
The bottom end of the arm has 6 huge piston rings in it. These were all in good shape so im not replacing them, I would have switched over to a set of o-rings had they been damaged. The bottom end of the unit where the PTO hooks to it, is held on with 2 huge banjo bolts with copper crush gaskets between the individual parts. One of them has an o-ring on it (1 1/8" x 1 3/8" x 1/8") and has a spring and ball check valve inside of it. I broke my vice trying to get the hex plug out of the end of it, so itll be cleaned and left alone as the ball has no wear marks or scoring on it.
Next was pulling the housing apart. There were 4 needle bearings (Torrington B-1314) that the geared shafts sit in. A goofy looking thrust washer on each side of the gears. On the outside were 2 - 1 1/4" snap rings that when pulled allowed the outside bushings, v-ring seals (4 on each side 13/16" x 1 5/16", plus 2 male v-rings at the same size), machine bushings, springs and bearings to be removed. The valve and lever that sits between the cylinder and the gear housing has a small shaft and 2 end pieces that use 2 - 1 1/8" x 1 3/8" x 1/8" o-rings and 2 - 11/16" x 7/8" x 3/32" o-rings, held in place by 1 5/16" internal snap rings.
I made a gasket to fit between the two halves of the gear housing and reassembled. I used a graphite packing material and cut several lengths to fit around the piston arm. My homemade wrench worked pretty good at tightening the big 2 3/4" nut to compress the packing. Dont make the same mistake I did and use 1/4" packing, 3/16" is ideal, it sure doesnt squish trying to get it in place...
Im almost done, all thats left is getting the frame, arm and pivot bars derusted and painted.

Jeff