Hydraulic Jack

Have 2 hydraulic floor jacks made in China. The jacks have a creepage problem (when the release screw is in tightly the jack still comes down).

One of the release screws is badly bent and the other is bent a bit. These were never overtightened.

I fixed this by fashioning my own screw made of 316 stainless steel 7/16" hex rod stock which is harder than the original standard steel. In addition, in the end of the screw you make a taper so the release ball fits in the center. In this way when it's screwed in the ball is forced to ride in the center of the screw and doesn't try to move to one side when putting massive pressure on the ball to prevent hydraulic fluid from coming back making the jack go down.

You'll need a lathe to complete the job but the pin will last forever. I tested mine a few times and it doesn't bend at all or creep down anymore. The one jack I have only had about 2 years (used maybe 10 times) before the problem developed. It's also extremely convenient to use a 7/16" socket to tighten or loosen the screw.

Post edited by: jmborchers, at: 2008/08/09 17:08

Great information, Jmborchers

Perhaps I should move this to the "tips" section in the forum? What do you think?

I think a lot more people would find it under cars better than the tips forum which is more generalized. But either would be fine.

Post edited by: jmborchers, at: 2008/09/02 23:32

old screw

You can see how bent the tip gets.

Post edited by: jmborchers, at: 2008/08/09 17:10

Here's the drawing. I've found this particular screw is used in many a jack's;

Pep Boys, AutoZone. If your jack was made in China it will probably exhibit creep over time. This screw fixes the creep problem but it has to be made from 316 Stainless steel because it's harder than the original steel.

Dimensions shown are in mm with standard dimensions in brackets. Not shown in the drawing is the taper I ended up adding to hold the ball on center.

Post edited by: jmborchers, at: 2008/09/02 23:06

This time I'll really add the drawing.

Here's a much better photo of the new one.