Floor jack no longer jacking

My long-serving 3.5 ton floor jack is suffering from erectile dysfunction. Operating the handle produces negligible movement with zero load, and none with any sort of weight on it. Given that it's pretty old, I'm assuming either worn out seals or lack of fluid (or both). It's a Craftsman, probably 20+ years old, made in China. I've never torn into a hydraulic jack before, and I'm not sure if seals would even be available for this thing. I can't see anything that looks obviously like a fill plug. If I can locate such a thing, I'm thinking the first step is to refill if the oil is low and see what that does. If it's not low on oil, well, I'm guessing I may just have to replace the thing.

Any advice on how to proceed from those who've dealt with repairing these things before?

Same thing happened to me a few months ago. 35 year old floor jack I bought new. Rebuild kits are available but just expensive enough that when bundled with DIY learning curve I chickened out and just bought a used equiv off the list of Craig.

My old Craftsman has a rubber plug for the fluid reservoir. The plug is painted the same color as the jack, so it's kind of hiding in plain sight. If my jack won't jack, it's low on fluid. 

On my small roller jack, a 35 cent o-ring fixes the piston at the base of the handle.  I've never had to go further in than that. I've replaced it maybe 5 times in the 30+ years I've owned it.

If it's low on fluid, you should fix the leak (grin).

I decided I should clean the thing up and look more closely for a fill port. Now I'm confronted with more than I expected, as seen here:

As you can see, there are three recessed screws, two with "Do Not Adjust" under them. There's also the one raised bolt in the center. The piston is on the left, held in (it seems) by a sliding pin that attaches it to the handle.

I'm not even sure what I'm looking at here. Could it be as simple as replacing an O-ring on the little piston on the left? Should I take "Do Not Adjust" at face value, or is that simply a liability-avoidance sticker?

I'm beginning to think that a trip to Harbor Freight may be in order tomorrow....

The fill plug will be near the base of the cylinder, not where you are taking the picture.

Does this help?

NGTD said:

The fill plug will be near the base of the cylinder, not where you are taking the picture.

OK, I found it. As suggested, it's a rubber plug. When it came out it popped like a champagne cork for whatever reason. Fluid is present but not filled to the top, which I'm thinking it should be, so the first course of action is going to be to get some hydraulic jack oil and top it off tomorrow, then see where things stand.

In reply to David S. Wallens :

Yes, it does, thanks. In the video he says the fluid should be up to the top of the inner cylinder and suggests overfilling is possible, which is not what I would have guessed. I'll get the oil and fill as he indicates and see if that solves the problem. Thanks.

Cool. Sounds like you're making progress.

And I just randomly found that video. As always, check the owners manual for your particular make/model. 

In reply to David S. Wallens :

I think the model shown in the video is the same one I've got. Looks pretty much identical. As far as an owner's manual, I'll have to search online and see if I can find one, as my paper copy disappeared probably two decades ago.

EDIT: Found the manual online. It says to fill to the top of the hole with the handle fully lowered.

Somewhat related, anyone know a good source of replacement handles? (i.e. a good place to get a big metal stick) I loaned mine to my parents and they lost the handle somehow.

IF you can get it to "jack up" after you fill it I'd just go get a Harbor Freight model as they sell ones nearly the same design.

I have an old Craftsman jack made in Taiwan not China and that thing won't die!

It's over 30 years old.

Anytime it doesn't work I just top off the fluid and it's working again.

In reply to 02Pilot :

Awsome news. 

slowbird said:

Somewhat related, anyone know a good source of replacement handles? (i.e. a good place to get a big metal stick) I loaned mine to my parents and they lost the handle somehow.

Plumbing supply place. Get a length of black pipe the right diameter. Easier if your old jack used a set screw, as you can drill and bolt if it isn't perfect. 

Edit: my jack has the opposite problem, it won't go down with a load. I already bought a replacement, but having 2 big floor jacks could be useful sometimes

I heard a theory that brake fluid was a decent fluid to use in a floor jack. Anyone have an opinion on this? 

pres589:

You -can- buy "Jack Oil."

O2Pilot:

On mine, I just have to disconnect and move the do-hickey that moves the piston, then the piston comes out easy-peasy. Mine uses a simple o-ring.  If it's anything more convoluted than that, you can hit up a hydraulics or farm implement store. Or an automatic transmission shop - they might recognize it.

Sears did sell repair kits eons ago, maybe Lowes now? A quick search came up with this outfit https://www.hcrcnow.com/shop/seal-kits/craftsman-sears 

My 20 yr old China jack had the same failure as OP, and of course I ordered a Harbor Freight o-ring assortment & disassembled the thing BEFORE watching a dozen youtube videos that suggested one simply add fluid.  So..don't do what I did.

Update: The good news is that I got the proper oil, filled, bled air, topped off, and the jack functions as a jack. The bad news is that it does so far slower than it should; every stroke gives me maybe 1-1.5" of lift unloaded. This jack is supposed to go up fast with no load, so it seems something internal has gone awry. It's probably just a seal, and thanks to the link above I see that kits are available for $30, but the number of seals and ball bearings shown in said kit is making me think seriously about just replacing the whole thing.

I'm going to let it sit overnight to see if there's any improvement (I didn't see any signs of foaming, but I suppose there may be some air somewhere that the bleeding procedure missed), then make a decision. HF looks to have a couple of versions on sale at the moment - any particular favorites?

Even then.. what's better than one big ol floor jack? Yes, two!  
I got a swanky aluminum low profile guy via Amazon but I still want to re assemble the big heavy boy. 
so there's a tip - get something light that has low ground clearance if you do sporty stuff. My pops pig iron harbor freight jack didn't have the clearance to escape the camaro lower crossmember after we did unspeakable things to it (big block swap)

also carrying a 50lb jack around sucks when it could be half the weight 

how do you "burp" the air out of the jack.

do you need to stand it up ? or ?????

In reply to californiamilleghia :

According to the manual I found for mine online, you rapidly pump the handle several times with the release valve open. It must have done something, as the fluid level dropped after I did it.

Cool. Now that the jack has burped, is it properly jacking? 

Or is it still jacked? (Sorry, just amazed it hasn't already been done...)