DIY: Floor Jack O-ring Rebuild

[MrPc]

I rebuilt my old imported jack a couple of years ago. It's an old Canadian Tire branded 2 1/2 ton trolley jack that I bought back in the early 80's. Many years ago it developed an internal leak, but I couldn't bring myself to throw out my formerly trusty big heavy steel jack for the sake of just a few rubber bits that needed replacing.

Sorry no pics of the entire jack, but here's what the it looks like disassembled:

Dismantled parts.

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Rebuild kits can be found for the well known US made floor jacks, but not for the cheap imported jacks. I looked!

After going through the garagejournal threads mentioned earlier, my solution was to dismantle the jack and carefully measure the old seals, as well as the dimensions of the cylinders, pump piston, rod, etc. Then I scoured the web for hydraulic seal suppliers and the pored over their websites looking for seals that would fit. IIRC, I had to substitute one type of seal for another--a loaded u-cup to replace a v-cup or something like that--and I went back and forth between metric and standard sizes looking for the closest matches. You have to match inside and outside diameters, as well as the thickness. Some of them have steps in them as well.

Here are what mine looked like:

Seal dimensions. Anybody know how to rotate the pic so it's right side up?

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Ram measurements:

Ram dimensions

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They go on the ram like this:

Cup seal on ram. Note step in seal.

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See that little step in the seal? I couldn't find one like that anywhere. I ended up getting a cup without the step in it, and then filing the matching ridge off of the backing washer to make it flat.


After much searching, I managed to find what I needed at Rocket Seals, in Denver: http://www.rocketseals.com Their service was good.

The parts arrived quickly; I put them in. My trusty old jack has been working ever since!

One other thing I learned: don't use a magnetic pickup tool to fish the metal check ball out of the casting! I did that and it magnetized the ball, which made its behavior inside the jack unpredictable and the pumping action erratic. That took a little while to figure out! I ended up replacing it with a similarly sized non-magnetized ball bearing that I had lying around. Big improvement!

Paul

[pkc303]

Thank you for the information. Really helps us out. Good post.

[cn90]

Almost 3 years now.
Zero external leak, bone dry.