I'm working on changing out rear springs and have a problem with my bottle jack. The jack has plenty of ooomph at first then runs out of gas about 3" or 4" into the lift. I have purged the air out of it as prescribed by the manufacturers but still no luck. I pumps all the way out without load but under load it acts like it's airbound before long. Any insight or tips?

Thanks,
Mark

 

Make sure it's full of fluid

 

Assuming it's hydraulic, the symptom could be caused by a bad seal.

 

I have filled the fluid and pumped it with the release wide open. Bad seal is a possibility, nothing leaking up top. Bad seal down in the lever? It does not look like there is a way to fix that one. What puzzles me is how well it seems to work before it fades out.

 

Pump it all the way out no load and then put your weight on it. If there's any give you still have air in it that needs purged.

 

Look at top of jack at top of barrel where ram comes out it looks like a collar or nut spray with oil push down check for bubbles then turn clock wise to tighten it down just did onetwo days ago doing my dually brakes if I knew how to post pics I would sorry

 

It is still spongy and when lowering I hear the sound and feel the feel of air in it when it bottoms out. I have run it through the purge process several times. It looks as though the oil is aerated. Maybe in time those bubbles will make their way to the top. I'll try another air purging before I give it one last shot before I just go get a new one. And maybe the hydraulic oil I used is not the right stuff?

 

I typically use ATF in mine.

As you get more air out, you might need to put more fluid in.