Rebuilding a hydraulic Jack... cornfuzed..

[Rogan]

Nope, I don't have a manual, and I don't know wtf I'm doing. All I can say is that it works when it wants, and that's not good enough.

Its a Central Hydraulics motorcycle Jack.

It doesn't leak, and it appears to be full of fluid. However, I don't know what all these are for:

Left side, no idea. Allen plug pukes oil when I open it. Right flat tip screw thingy when you take it out has a flat tip screw adjuster inside.

Any help? Sometimes the Jack works full stroke pump. Sometimes, partial stroke. Sometimes it doesn't hardly move.

Sent from my PC36100 using Tapatalk 2

[bh115577]

Rick, Go to this link: http://www.harborfreight.com/automotive-motorcycle/floor-jacks/15-ton-lightweight-aluminum-racing-jack-with-rapid-pump-68054.html and download the product manual. There should be instructions in it that will tell you how to bleed it out. Different jack but steps should be similar.

[Wild and Free]

A simple way to blead most jacks is to leave it in the lower or released position with the valve open and then pump it for a while. This will usually cycle the air out of the valve. Works on a lot of jacks and pumps but not gauranteeing it would work on all.

[flagmanruss]

Manual hydraulic jacks are pretty simple creatures. It'd be easier if we had X-ray vision. You have a reservoir. You have a pump which draws oil from the reservoir & forces it through a check valve into the piston cylinder. You have a release which is nothing more than a bypass from the cylinder back into the reservoir. If it lifts & holds & releases when you turn the handle, then that part is ok.If there's oil in the reservoir, that should be all that required.It is possible to blow the O-rings out of the cylinders but that's pretty obivious under load. I used to blow the seals out of jacks jacking up boat cradles... with 40 foot Concordia yawls in them! The yard sent them out to be "rebuilt" but I don't think the did anything more than add oil.The pump... there could be a blown seal in the pump. My brother has had some luck matching O rings at the auto parts or hardware store by trial & error... he says something about jacking up train engines is tough on jacks. There could be something wrong with the check valve.

[Rogan]

Thanks, guys.. http://www.harborfreight.com/lightweight-aluminum-motorcycle-lift-94715.html is the actual lift. I never thought about finding the product manual; good call! At any rate, I now know how to change the fluid, bleed it, etc.. and know what all those odd-balled screws are ;)

[flagmanruss]

It's easy to stand too close to a problem... when it's yours! An outsider is not emotionally invested & not frustrated yet.

[anoldbiker]

Their manual at: http://manuals.harborfreight.com/manuals/94000-94999/94715.pdf looks similar and the fittings are similar to your that are on page 7

[hd99fxr3]

It's amazing how far a fella will go to not have to read the manuel. I'm quilty of it as well.

[Rogan]

I read it, once I found it online. Still, though, it doesn't really break down what I need broken down to troubleshoot. I think it's all in the cylinder assembly, maybe a piece of trash or something in the fluid that occasionally doesn't allow the valve to close completely.. I dunno..