Not sure if this will help you, but it worked for my Craftsman jack that had similar issue. This is an excerpt from another forum I am part of.
I did a search for Craftsman jack leaks, and this seems to be the best thread that I could find. Nothing came up when I searched for jack 50240.
I bought a Craftsman jack (part #50240, 3000 lb capacity) a few years ago, and it has been leaking fluid for the last year or two, most noticeably when it is being stored and not when supporting a load. This failure is common for this jack if you Google that part number.
Aside from the leak, the jack is pretty decent for the typical made in China crap (not too heavy aluminum/steel construction, was reasonably priced, goes higher than most HF jacks, starts out lower than most jacks).
From what I have seen, most people just ****can the jack when it begins leaking, as Sears gets something like $125 to fix it. Since that's about what I paid for the damn thing it the first place, it wasn't an option for me, and neither was blowing another $150 on a new jack. I also figure that the average person who posts "product reviews" online probably isn't able or willing to tear into the broken item to attempt a repair before throwing it out.
Fortunately, for many of us who own this jack, this leak can be fixed relatively easily. It appears that the pump piston (the one that the handle actuates, not the ram) is the culprit, but the leak actually comes from the pressure release valve (the one that is opened when you turn the handle to let the jack down). You will need an 11mm Allen wrench and a 12mm socket. Unbolt the jack handle from the frame with the 11mm Allen wrench (note that 1 side is left hand thread, the other side is normal). With the handle out of the way, remove the 12mm head bolt that holds the retaining tab for the pressure release valve U-joint. Then, unscrew the PRV all the way and pull it out, but be careful, as some fluid will spray out when you remove it, and there is a single ball bearing inside that may also shoot out. There is a small rubber O-ring around the PRV that needs to be replaced, so I used one that was just a little larger and fit more snugly in the bore. Oil the O-ring a bit and reassemble everything.
So far, so good. Cleaning up the puddle under the jack has been a daily task recently, but it's been together for 24 hours, with a fresh fill of jack fluid, and the floor is dry so far. Let's hope that it holds up.
Same happened to a floorjack i bought at wally world. I opened the fill hole and put a few drops of brake fluid in the oil. (used the same trick to stop oil leaks on the pumps at my car wash years ago--Brake fluid softens and slightly expands the rubber seals and o-rings). I might use mine once a year--Been a couple years now, and mine still not leaking. Worth a try.
And for all the jack stand comments-where did the OP say he wasn't using jack stands?
Location: 1.Just because I'm paranoid doesn't mean people aren't out to get me... 2.That which does not kill me will probably hurt like hell. 3. Islam & the SC is the enemy.
Originally Posted by C5iveRacer
I bought a 2 1/2 ton Sears Craftsman floor jack about 2 years ago, I think I have used it twice, maybe 3 times. I go to use it today and as I'm jacking the car it starts spewing oil out of the top of the piston like the Deepwater Horizon in the Gulf
Now it won't work at all.
I know Craftsman hand tools have a lifetime warranty because I have used it before but I'm wondering if this would apply to a hydraulic jack?
I have a mid sized craftsman jack ( can't remember the weight rating) and i use it semi regularly and it hasn't had one issue sense i got it in 2000. Idk if they stopped making them the same way (which i doubt) or people just fail at using a jack properly.
the key to keeping a jack from failing is to use it and when you do make sure it's fully shut when jacking. I have held the front of a car or corner of a car for days when tearing things apart. Of course this is not the recommended way to use a jack nor do i advise it with most people but it shows that the jacks work just fine. and i think it's user error or lack of use that makes these fail.
It's a crap shoot! I bought this same US General from HF almost 7 years ago and have had zero issues with it. I recommended it to friends who then purchased them from venders at Carlisle. I think 2 out of 3 of those failed within the first 2 months.
I don't know what happened to your jack...my 2-ton Craftsman floor jack has worked great for years. I do, however, replace the jack oil every year or two.
Sears used to be great about standing behind their products...or at least servicing what they sell. No more. I had a Craftsman torque wrench repaired at the local Sears Service Center a couple years ago. Now, the locking ring broke on the same torque wrench. I drive to the Sears Service Center but it's closed down. I take the torque wrench to the Sears store and they inform me they don't service a torque wrench...they say call their toll-free service number. The national Sears 'service' center is no help at all. The only things I ever buy at Sears are tools but if they won't repair a Craftsman tool I'm losing faith.