Engine Hoist Slow Leak - Help me Fix it!

Hydraulic jack oil is available at many auto parts outlets and at most Tractor Supply Stores, I doubt it would hurt anything to blend the original with replacement oils if marked for suitable hydraulic jack use.
 
Just as you can get Power Steering/Transmission/Diff fluid that also stops leaks, so you can get hydraulic jack oil with a leak sealing additive.
It's just a regular jack oil with something added to swell the seals.

I bought some from Wal-Mart to keep for an emergency.

IMG_1726.JPG

M

IMG_1726.JPG
 
joe_m said:
The interesting part (to me at least) is that after the impromptu disassembly I was able to use it to lift a lathe with no problem. The leak didn't show up until now - 5 months later.
Click to expand...

Joe, I am thinking that because of dirt doing some damage to the seals or valve seat it worked fine a couple of times but now the damage is becoming apparrent.
Good luck anyhow.

Cheers Phil
 
I suppose it's conceivable that the ram sits in a counter bore in a piston that stayed in the cylinder, perhaps held in place with a snap ring of some sort that is designed to give if the ram is over extended. If the ram is not properly seated in the piston recess, the piston (usually they are fairly short) could be cocked in the cylinder bore, allowing leak-by on the piston seal(s). I haven't examined too many of these engine cranes, but those I have seen are welded cylinders, so there's only one way to service them and that's to cut off the head and re-seal the piston and the head, and weld it back together. The better cylinders have a head built in such a way that a bulkhead is retained by a large internal snap ring that, once removed, allows the bulkhead to slide out. It will have packing on the inside that seals against the ram, and a gasket or seal that takes care of the fit between the bulkhead and the upset end of the cylinder. I have my doubts about the valve being the culprit, after knowing the ram came completely out.
 
if the oil is slowly bypassing around the piston, the oil woud then be on the "rod" side of the cylinder and when the cylinder is fully extended, that oil would be pushed out the end of the cylinder. . . . the end of the cylinder has only a dust seal to prevent crap from entering the top of the cylinder, no seal. . .

usually, the seats / chrome balls inside the valve assembly become contaminated and don't seat fully. they usually require a new ball and "coining" the seat with the new ball.

coining means to smack the ball hard, using a drift punch and heavy hammer right against the ball.

i could not believe that would work until i talked to owatana tool hydraulic service dept., OTC and thats how they said to fix one of their expensive jacks i was having trouble with.

99.9% of the jacks do NOT have replacable seats. . .and most of the cheap ones have inferior castings so even coining will not work.
 
I went out this morning to see how much it had moved and of course it had "deflated" almost all the way. When I opened the valve it only had another 3 inches to settle.
I must have missed a tip up above that said do NOT open valve all the way because while I was there I unscrewed it all the way and fluid shot out of the hole and all over me, ruining a perfectly good $3.99 Wally World 100% imitation cotton t-shirt. I'm still not sure of the color, but it seemed more clear than anything else. And very thin. I'll take the assembly off the hoist, find some fluid, try to add some and pump out any bubbles and if it works, great. If not then I'll just throw it in the back of a shed with all the other misfits.

thanks
Joe
 
I have a harbor freight 2 ton engine hoist, and have had no problems with it for the 8 years I've owned it. Thats not saying the one you get will be perfect, and the one listed is a three ton lift and there are 8 ton units but these were $59.99 (I think). Remember the rating of the crane and the jack are two different ratings, just so you'll consider this if looking for a proper replacement. I bet your Delco unit was made over seas too.
 
You must log in or register to reply here.
Back
Top