It has been a long time since I have checked back in with this thread I started. Ever since I bought this S-4 jack, I had always owned a "cheap" aluminum racing jack. That was a purchase I made when I was young and did not know much better, but it was always frustrating to me. I could not stand the lack of quality of the jack, as well as some annoyances with the reservoir becoming pressurized and pushing oil out of the release mechanism, which was sealed with a single poorly fitting O-ring. My S-4 was functional, so it saw the most use during this time and I was afraid of really digging into restoring the S-4 until I had a reliable second jack. Finally, last year I became frustrated enough with the racing jack, that I decided to buy a Compac 90530 2 ton jack. With the Compac in use, it was finally time to turn back to the S-4 and give it the repairs in needed.
If you can remember back to the original info in this thread, my jack had a few rough spots, but was otherwise functional. One of the big annoyances with the jack was the slop in the jack release mechanism. The majority of the slop came from the two universal joints and the pinned slider that connects the joints.
I was able to drill the pins out and fully disassemble both universal joints. I don’t know the year my jack was made, but this is likely what 60 years of wear looks like on the 1/8” pins and bores for the universal joints.
It was not worth trying to repair any of these worn parts, so I started with some 5/16” square stock and ground and filed them to size, then drilled new holes.
The original design of the slider section of the universal joint used a single round pin that interfaced with the slot. Of course, over time, the pin wore some and also wore the corners off the slot.
To repair the slot, I welded a small bead on each side of the slot and then filed the surface back down with a small needle file.
It would have been easy enough to simply put a new pin in and call it a day, but I could not help myself. I decided to convert the pin into a flat plate with a significantly larger surface area. This should spread the load over a wider bearing surface and should prevent it from getting sloppy for many more years. I will probably never appreciate this work, but one of my children may.
With all of the parts repaired, I installed new 1/8” pins and hammered the loose ends over to rivet the joints back together. With everything fully assembled, both universal joints and the slider only have less than 1/16 of a turn of slop, which is a large improvement from the original ½ turn of slop between all the connections.
I have not decided yet if I want to try to repaint any of the parts or clean them up good and wax them or clear coat them. The main bod of the jack has original paint in decent condition, so I don't want to lead myself down the path of repainting everything to get a good color match.
I will continue to post as I make repairs, but I already ordered a new seal kit and will be completely going through the hydraulic unit for this jack.
