!!! Wait !!! I’ve had one of those Craftsman aluminum “racing” floor jacks since I bought it new in 2006. Paid $100 on sale. I liked it because it was rapid pump and weighed less than a steel Jack of the same size.
However, it also leaked like a sieve every time I used it!! Never touched the screw that said “do not adjust”, would only open the filler screw and add more fluid.
But this thing was absolutely ridiculous!! No matter WHAT I did, every time I used it the fluid would leak out (the top mostly).
So I returned it, but the guy at Sears only had a tiny one in stock to replace it, I didn’t want that, so I dragged it back home. Then I forgot to go back again, fell outside the warranty period, and was stuck with it.
But then I started experimenting with it and here’s what I found: if every time after I use it I immediately “close” it by quickly turning the handle all the way (tightly) to the right, it holds the fluid for multiple uses. I had been leaving it open (left) and I believe air was getting in there.
Used to be that I would have to always open the screw and add fluid before each and every use, but now I can’t remember the last time I had to refill it! Every time I take it out now it lifts the car no problem!
I had even bought some of that special “sealing” Jack fluid because that’s what I was going to try next, but I’ve never used it.
So fill your Jack one last time, follow the procedure for bleeding out the air inside, then always remember after letting the car down to turn the handle all the way clockwise to “close” it to keep air from getting back in