US General aluminum floor jack no longer jacking

I bought this from HF forever ago. It is (was) a great jack. Lightweight but sturdy and jacks to a very tall height.

It recently stopped working. I assume a seal (or seals) has gone bad. Is there a relatively simple rebuild process? New jacks aren't that expensive but I'd love to rehab this one instead of pitching it and buying new. Any advice?

Looks just like this:

Make sure the oil level inside is high enough, too. I had one stop after just a month, but all it needed was to be topped up.

Mine intermittently will have one of the plungers no longer..  plunge.  Or I should say spring back from plunging.  This renders the jack hopelessly useluess until I pull the plunger appart and clean it.  I'm not sure where all the metal and dirt and crap that gets into the plunger comes from.  

+100 on checking/adding oil as the very first thing to do, and even applies to every brand new jack right out of the box

https://www.hcrcnow.com/shop/seal-kits/u-s-general

https://www.garagejournal.com/forum/threads/overseas-jack-rebuild-help-tutorial.51105/

https://www.google.com/search?q=site%3Agrassrootsmotorsports.com+jack+rebuild

Mine is coming up on five years old, guess I should check the oil! It gets used four times per every event. 

my old hammer store 1.5T aluminum jack only lifts with half a pump now, 9 years into ownership.I should probably clean it up and check the fluid. 

bobzilla said:

my old hammer store 1.5T aluminum jack only lifts with half a pump now, 9 years into ownership.I should probably clean it up and check the fluid. 

It may just need bled if you haven't done that recently..

I did one of them in after trying to level a beam at a camp.  The plunger at the base of the handle stopped returning. Disassembly and fixing the rolled seal/ o-ring has it back in action.  This thoroughly reinforced my Jack stand usage. 

WonkoTheSane said:

bobzilla said:

my old hammer store 1.5T aluminum jack only lifts with half a pump now, 9 years into ownership.I should probably clean it up and check the fluid. 

It may just need bled if you haven't done that recently..

never been done. 

I was going to throw out my old floor jack until I bled it. Can't believe I didn't know how to do this:

https://knowhow.napaonline.com/floor-jack-wont-lift-heres-a-quick-fix/

Here's a good video I found on filling & bleeding one.  If you search youtube for "bleed harbor freight jack" you'll get a bunch of different hits if your model varies too much from this to make sense of it:

Yeah, I have that exact jack that I have had for 15 years (?).  I did have some pump up issues at one point.  Bleed it, and it was fine.  Probably should check that again at some point.