I'm sure someone has had this problem with a hydraulic jack or in this case the hydraulic cylinder on my engine lift. (cherry picker)
It won't hold and tightening the little screw that's suppose to make it hold does no good. It slows it down but won't stop the load from going down. Maybe something with the screw or with what it seats against inside. I took the screw out and it does not look perfect. Are replacements available for these screws. I bought the lift brand new but it's a made in china. It has had very little use and leaked down from the day I got it but it's worse now.
I think it's suppose to hold by the tapered sides going into a hole in the jack but the screw also has a "dimple" on the end and am wondering if they shut off that way on the end of the "pin".

Thanks for any info.

 

There should be a ball bearing under that dimple. Look inside at the seat and see if the ball bearing has been driven into the metal seat cracking it. The problem with most jacks is that they have been overtightened. It really only takes finger pressure to tighten the valve on a jack. Unfortunately most people I have seen tighten them like they were gorillas, -ruining the jack.

 

I'll have to check that out. The trouble comes when something is wrong and it won't work with a normal light tightening. At that point it seems the only thing to do is tighten it more but the problem only gets worse. Course if it won't work with the normal light tightening I suppose it should be taken apart to check and repair it if the bad part can be fixed or located somewhere so it can be replaced. OR I suppose replace the whole "8 ton cylinder". ?

It is hard to see inside. Not much space. Probably pulling out the rubber seal will help. Then the rubber seal will be shot and look for a replacement for that also.

Thanks

 

i just replaced the lift cylinder on my home engine hoist with an air operated unit from harbor freight for $69

 

That sounds like a good idea. We have a local Harbor Freight. Unless I can get mine to work properly. Air operated sound better then pumping that handle.

Thanks