A few years ago I bought a 3.5 ton Sears Craftsman "Professional" floor jack. I didn't know it at the time, but at some point Sears stopped making their jacks in the USA and production shifted to China. The jack I bought was made in China.
Just google "craftsman floor jack" to get a feel for what happened to the quality of the jacks in recent years. Like many others the power unit on mine started to leak after the warranty expired. Sears doesn't offer a repair service and they don't sell parts to repair the power unit. You can buy a new one, but the thing costs about $175 these days. For that price you can buy a couple of brand new jacks at Harbor Freight, so that's what I did. It seemed like a waste to throw it away, though, so I put the Craftsman aside until I had some time to look into it more closely.
Last weekend I gave it some thought. I did some digging into part numbers, replacement part numbers, manufacturers, and I made some phone calls. No one wants to rebuild power units made in China. However, with a lot of detective work I managed to find a seal kit for my power unit that includes all of the o-ring seals that typically go bad. Here are the part numbers:
- Original power unit part number: 5954 (currently $173.49 from Sears)
- Replacement power unit part number: G59305-0001 (manufactured by Shinn Fu Company of America, Inc. (SFA), http://www.shinnfuamerica.com/, current price $131.27)
- Seal kit for G59305-0001: G59510-0000 ($11.55 plus shipping from SFA)
I found the seal kit part number and an assembly diagram for the power unit by looking in the owner's manual for another jack that uses the same G59305-0001 power unit, the Omega MagicLift™ Hydraulic Service Jack Model 25030. You can find the manual on the SFA web site with a little searching.
You might be tempted to disassemble the jack, measure the o-rings, and find replacements. I found them to be odd metric sizes that weren't available at my local parts store. It might be possible to find them at a place like McMaster-Carr, but they typically sell o-rings in packs of 10 or more. I didn't need that many.
Having said all that, I'm not suggesting that everyone go out and try to rebuild their leaky Craftsman jack. If you take it apart without knowing what you're doing you can screw it up badly enough to make the jack either non-functional or dangerous. The point of this post is to let people know that a seal kit exists for at least one Craftsman jack, and in the hands of a professional the kit can be used to repair the jack.
If your jack uses a different power unit you might get lucky by using the same process I did. See if Sears lists a replacement power unit with a new part number. Search for that part number on the SFA web site. If it turns up in one of the jack manuals you might also find a seal kit part number in the same manual.
Some last notes: there are little stickers on most hydraulic jacks that warn you to not mess with the valves. Believe them; they're part of the pressure control system. If you lose any of the internal valve parts (spring, ball bearings, etc) you're SOL because they're not included in the kit and the jack won't work if those valves aren't working. If set improperly they can lead to over- and under-pressurization problems.
Never work under a car that's only being supported with a floor jack. Use high quality jack stands.