Hey,
I have an old engine hoist (shop crane) that has not been used for a long time and now the hydraulic jack does not work as it should. When I want to raise my engine and I pump the jack, it stops as soon as it starts to feel the resistance and it lowers down a bit. I checked the oil in it, there was just a little of it inside, so I drained the oil and replaced it with hydraulic oil. I drained it through the release screw and poured new one through the seal in the middle of the jack in lying position so that I could fill it up in full. Now it is even worse than it was because it lowers down a bit even during raising it... What did I do wrong and how should it be fixed?

 

Sounds like the jack has bit the dirt! 2 options, somehow find a rebuild kit for the jack, go to somewhere like northern tool and find a replacement jack.

 

sounds like you've got some air locks in it.

 

what to do then?

 

Best thing you can do in this case is replace the cylinder they are'nt that expensive and trying to rebuild it is a pain and might not be safe for a non-professional tech. Remember your life may depend on the jack working as advertised.

 

that was disouraging... Anyway I took it apart and... I fixed it some seal was flipped My friend told me that it happens in these cylinders...