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View Full Version : OT..Hydraulic jacks



torker
05-13-2004, 07:27 AM
Heys guys... I have nearly new engine hoist with a long stroke jack. I lifted a refurbished box onto a pickup with it and it swung up and sheared off the rubber plug that is on the outside of the ram about halfway up. Now the jack gets stuck once in awhile. Must be the little piece of rubber stuck in something. Went to local hydraulic shop for advice...as usual..."Bring it in and for $80/hr we'll fix it for you". I need to take the jack apart. How hard is this? Do I have to take the big end off or can I just take the pump section apart and somehow grab the piece out of it? and what do you fill these with and how do you determine the fluid level? When I took it to the Hydro shop it fell over and some fluid leaked out so I'm not sure how much is missing. Thanks!
Russ

thistle
05-13-2004, 07:48 AM
iam just replacing one of those 8 ton long reach rams-

if you go to the harbor freight website and look for the 8 ton long hydraulic ram -there is a pdf file for the manual which give s an exploded diagram for the ram.

might help.

torker
05-13-2004, 07:52 AM
thistle...thanks! I'll have a look. Never had one apart before so that might help.

wierdscience
05-13-2004, 08:12 AM
There should be a big nut near the top of the jack just below the end of the ram,clamp the jack base in the vise and break that nut loose with a pipe wrench or end wrench if you have one big enough,unscrew it and the cap and resivoir should come off,once the cap is off the ram will slide right out.

If you take the valve body apart be careful not to loose the check balls in the bottom.

When you refil the jack,colapse the cylinder all the way,stand the jack verticle and fill through the hole that the rubber plug fits in,it should fill to a point about 2" lower than the hole,the plug is just a breather.When you are ready,pump on the handle with the valve open for a few strokes then close it and pump the ram to full extention,open the valve and shove the ram down and that should remove any excess air,if there is a little bit left use the lift to pick up something heavy and then slowly release the valve and the remaining air will will gas off in the resivoir.

As for oil R&O hydrualic oil,not ATF or brake fluid.Your hydrualic shop should have some.

[This message has been edited by wierdscience (edited 05-13-2004).]

torker
05-13-2004, 08:35 AM
Wierd...Thanks bud! I owe ya! Was hoping I didn't have to take the big nut off but it doesn't sound too hard after your explanation. Thanks for your time.
Russ

thistle
05-13-2004, 09:50 AM
http://www.harborfreight.com/manuals/36000-36999/36397.PDF

CCWKen
05-13-2004, 09:46 PM
That plug is the fill hole. You may not have to take it apart. If the top sheared off the plug, the part inside is too big to do harm and too small to make a difference. Some of these jacks come from the factory with crap in them. Opening the valve, lifting the arm and letting it return will usually clear the obstruction.

Your problem sounds like a bent shaft. When you say it sticks, is this comming down or pumping up? No lift on pump?

torker
05-13-2004, 11:17 PM
Ken...The forth time I used it, right after I lifted the truck box, I was lifting my mill onto the stand. It was easily lifting it when all of a sudden it quit lifting and dropped a couple inches. I let it all the way down and tried it again, this time it worked fine. It may again but I'd like to find out why it quit and dropped like that. Kind of nerve wracking when you have your hands in the way while positioning a heavy engine etc. I just figured maybe the little rubber tit that dropped inside might have something to do with it. It never had any oil leaks or anything else to indicate a problem. It is low on oil now but I haven't filled it up yet...was waiting to see if I had to take it apart.
thistle..Thanks for the link!
Russ

torker
05-16-2004, 07:49 PM
Thanks again all!! Took the jack all apart as per wierd's instructions. Ken...you're right, that thing was full of crap from the factory. Lots of metal chips etc. It looked like the plug had a little ring mark on it from being sucked into on of the oil passages. But there was so much other junk in it that it could have been anything. Glad I took it apart now...who knows how long it would last with all tha metal passing through it. Just lifted the big block into my racer with it and it worked well!
Russ

ibewgypsie
05-16-2004, 08:33 PM
Them jacks are throw-a-ways..

At $40 I won't spend too long working on them.

I think I gave $40 for the last one.. Not real sure.. I have a orange HF one on a motorcycle lift. The HF engine hoist has a red one.. not sure since it has been borrowed and gone so long.

I used to work on my vcr, spent about six or seven sessions of about 3-4 hours each, repairing it each time. I then bought a new one for $99. (not broke since). Big savings.
I think I disassembled the vcr for parts. Time is money if your time is worth money.

No pics of the racer big block? them are expensive toys.. big block=big money.. (big power too)

David.

[This message has been edited by ibewgypsie (edited 05-16-2004).]

wierdscience
05-16-2004, 09:24 PM
If you guys need to replace one the best one to get is dark blue and has a double action pump(handle pumps in both directions)they are better by far than the rest of the Chinese makes and move a lot faster with the double pump.