Do Hydrualic Jacks Always Bleed Down?

[dibbons]

I noticed the small block 318 hanging on my new cherry picker (just a few inches off the concrete floor) is slowly working its way down to the bottom. I noticed the same thing happen with my new floor jack, when I used it to support the transmission when I extracted the motor, after so many days it was no longer supporting the tranny. And I know the valves are both closed on both the floor jack and the hoist.

 

[72bluNblu]

They shouldn't if the valves are fully closed. If they're losing pressure then the seals aren't doing their job and there's some kind of leak down occurring.

Now, that said, they also aren't really intended to be supporting weight for long periods of time. If you need to support something long term in a static position you should be using some kind of fixed stands, not a hoist or a jack.

 

[Tooljunkie]

No hydraulic cylinder is that oil-tight. They would sieze.
Engine hoist- cut a piece of angle iron as long as the extended rod and clamp it on. Then set the load on the angle iron. Careful not to nick or scratch the rod.

 

[67Dart273]

I would NEVER leave an engine hanging on a hoist for extended periods. There is simply way too much that can happen, ESPECIALLY hydraulics and ESPECIALLY a cherry picker

 

[dibbons]

It's only 3 inches off the ground.

 

[famous bob]

I would NEVER leave an engine hanging on a hoist for extended periods. There is simply way too much that can happen, ESPECIALLY hydraulics and ESPECIALLY a cherry picker

Don't trust the break down cherry pickers either !