bottle jack problems

[jeeper]

So yesterday after work I did an oil change on my daily driver and when I was done with that I thought I would spend an hour or so cleaning the mess off the used NV4500 I just picked up.

I got my engine hoist in position and realized it didn't lift.

This has happened before when I've left it outside. It gets water in it. I put my oil change bucket under it and removed the screw. Sure enough a milky water started coming out. I pumped it a bunch of times to help get all the contaminated oil out. Once I wasn't getting any oil out I put the ball and screw back in.

After I put new hydraulic jack oil back in it still doesn't work and I've never seen it do this before. It seems the check valve below the piston is stuck open.But only after the pump lever is used. If I lift the arm of the hoist manually and pump the lever a few times the arm will stay up and I can loosen the screw to bleed it back down. But if I pump the lever the arm only lifts as long as the lever pressure is maintained. Putting pressure on the arm also puts pressure on the pump lever.

I've never had this problem before so I'm assuming I will need to pull the cylinder apart but before I did I thought I'd see if anyone else has had a similar problem and what they did to fix it?

[67smith]

New bottle jack on mine, what likely happened was the seals in the pump handle went. It's 50/50 wether it would actually hold weight either. You might be able to put body weight on it, but 500lb could collapse it.

I want to say I paid $50 for the new one, worth it for me over tearing apart the old one and scrounging for seals.


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[Don Cavey]

And, the check ball(s) are likely steel and if they rust, they are history.

Harbor Freight has them for sale. I got one to replace the one in my engine hoist but have yet to even see if it fits. I know, lazy...

[kwai]

replace or rebuild. I have had good luck rebuilding my hydraulics for presses and jacks. I don't do it myself but take it to a guy who knows what he is doing and how to test it when he is finished.

As Don said, you probably have rusty balls caused by not enough use.

[Subybaja]

As Don said, you probably have rusty balls caused by not enough use.

Yes, I am 12yo.

[jeeper]

Now that's funny right there...

[Don Cavey]

Yes, I am 12yo.

Age has no bearing on that!

[jeeper]

I ended up getting a Harbor Freight long ram jack rated at 8 tons. It's a little heavier than what was on there but it seems to work fine.

I will probably disassemble the original now that I have nothing to lose to see if I can figure out why it is operating the way it is. I'll try to remember to get some pictures if I do.

[Don Cavey]

I ended up getting a Harbor Freight long ram jack rated at 8 tons. It's a little heavier than what was on there but it seems to work fine.

I will probably disassemble the original now that I have nothing to lose to see if I can figure out why it is operating the way it is. I'll try to remember to get some pictures if I do.

That will be helpful. I got one of those HF rams as well but have not put it into use yet.

Thanks!