Sears lift hydraulics problem

[MarkT]

Anybody run into this one?  Where was the problem?

My Sears standard ATV jack I've had for many years, haven't used it in a year or so.  Usually use it only for the Wing, have other jacks for the Valk.  Anyway, I was using it to elevate the back wheel while the Valk was on the big jack, and while lowering it froze.  Stopped cold like it hit a stop.  No, it's not the safety bar.  Couldn't get it to lower even standing on the lift.  Playing with it, found the problem to be intermittant, and happens with the lift at different heights.  Might help to raise it a stoke or two then hit the lower pedal.  Like a check valve is dropping in & blocking the hydraulic flow. 

[olddog1946]

I had that happen on an engine hoist I had. OF COURSE, it happend with an Oldsmobile big block hanging on it, wouldn't go up or down and ended up using a prybar under the lift to dump the whole thing over. Turned out the valve for the release was broken internally.