Any Tips To Get Bottle Jack Working?

[HHR]

A friend just gave me his Larin 1500 pound ATV/Cycle jack in non working condition. He had unscrewed the release valve on the bottle jack portion so far that it and a bunch of oil came out. Hasn't been used since and I tried to add oil and bleed the jack today. The process I used was to open the valve one turn and rapidly pump the lever. Then I left the valve open and inverted the unit with the pump handle in the up position. Once inverted, I moved the pump handle to the down position and flipped jack upright. I repeated this 5 times. I would occasionally remove the oil fill plug to let any excess air out. Once the piston started to move, I pumped it up a few inches and inverted jack while allowing piston to retract.
After spending over an hour repeating these steps, the piston will rise like it should, but won't hold under more than 15 pounds of force.
Does anyone have any tips, tricks or additional things I could try before tossing this thing?

 

[Steave]

Instructions on most bottle jacks says to remove the filler plug (or screw), open the release valve a round or 2 then pump your jack at least 20 full strokes, then tighten the release valve, replace the filler plug and you should be ready to go. If it still won't hold a load repeat all steps. Don't turn the jack over as that's how they usually get air in them to start with. When the release valve was opened to far the sealing ball might have got lost. It looks like a BB and is located in there usually behind a spring.

 

[Steave]

I should have mentioned that whatever position the jack mounts in is the position you want to be while bleeding. Some jacks are mounted laying down is the reason I mentioned this especially on some of the motorcycle lifts.

 

[HHR]

I think it's missing parts because I did take out the release and there were no additional parts that were behind it. Come to think of it, most release valves on jacks I've used have a somewhat progressive feel as you tighten them up (like there is a spring behind them) and this one is not like that. It turns the same until it bottoms and stops immediately. Guessing I'm SOL on finding parts for this thing.

 

[Steave]

Since it will raise some your pump part is probably ok so it sounds like it is something wrong in the release part. That's about all there are to a jack. When you look into the hole with the release screwed out you might could tell what makes it seal and if you think it is indeed the one that had the little ball you might could find something to replace it. It's probably about the size of a BB won't hurt to try it. I like tinkering with stuff and fail more than I succeed but its still fun.

As far as finding parts I don't have any idea where to even look unless it's a brand name jack such as enerpac or blackhawk.

You could always just go buy another jack for your lift but what's the fun it that.

 

[Gary Fowler]

A 4 ton standard hydraulic jack is less than $20 so it would be cheap to replace.

 

[drizler]

A 4 ton standard hydraulic jack is less than $20 so it would be cheap to replace.

HARBOR FREIGHT. When it comes to bottle jacks Chinese works as well as anyone else's and are cheap

 

[Paul Thornton]

Search u tube, there is a great piece on there about bottle jacks.

 

[Egon]

Check valve?

 

[HHR]

I'm still looking for my stash of ball bearings to try one in the release valve.