air/hydraulic jack leaking question

[The Cobbler]

I acquired an air over hydraulic 12 or 20 ton jack ( not sure no markings on it)
it seems to work fine, doesn't leak down etc but the rod is wet with oil when it extends. the jack is damp with oil from the seeping I imagine. is there an easy fix or should I just leave it as is? is it unsafe? there's about a 3-1/2 " nut on the top, if I remove that is there an o ring beneath that that wipes the shaft?

 

[EDGAR]

Yes, there is an o-ring inside the big nut sealing the ram, but it leaking a bit does not make it unsafe. As long as you don't lay the jack on its side, the oil won't leak out from the oil tank. Still, enough oil can seep out every time the ram is raised that eventually the oil level may get low enough to prevent full extension of the ram. You can use it as it is until it requires major servicing and at that time you can replace all the seals.

Anyway,removing the big nut requires a vise solidly mounted and the use of a pipe wrench and a 4' or 5' pipe to serve as an extension as these nuts are tightened pretty hard (at least most are).

If you decide to replace the o-ring, then it is a good idea to replace all the other seals at the same time. Be aware that some import jacks use a 3.5 mm cross section oring while others use a 4mm, so accurate measurement of the o-ring is required as a 3.5 mm will not seal a ram requiring a 4mm CS o-ring.

Below is a link to a service manual for an Omega 12 and 20 ton. In the manual there is a parts breakdown which shows you the parts of a bottle jack. Yours may not have the same parts but it gives you an idea of what you may find inside.

http://www.omegalift.com/Owners Manual/18206C 20TonAirActuatedBottleJack/1131

 

[The Cobbler]

thanks a bunch!
are parts available as a kit or do you just have to piece meal parts?

edit, I see there is a repair kit listed.

 

[Hiball]

If the Ram is wet with oil there is only a handful of ways oil is getting on top of the piston seal.

1. Ram Piston seal is Weak, it's extremely plausible that a hardened seal can allow startup leakage and seal under load.
2. Jack has a relief hole in the cylinder and/or the reservoir has been extremely overfilled or has been laid on its side, which allowed oil to make its way on top of the piston seal.

Regardless the rod seal is not keeping up its end of the deal, whether it's a weak Oring or a issue with the Rod finish, it's hard to say without knowing more details.

 

[EDGAR]

Well, you did not mention the jack's brand, so a kit for an OMEGA may not have the parts you require. If the brand is unknown, the parts have to be measured and bought either a your local hydraulic shop or online. See below one site where you can get the O-rings and the u-cup (assuming yours uses an u-cup and not the o-ring and o-ring retainer found in some jacks). Often, buying just the parts needed is cheaper than buying a whole kit.

http://www.theoringstore.com/index.php?main_page=index&cPath=371_690

http://www.theoringstore.com/index....368_12&zenid=ec4974893ef5609ab409106195e0a303

 

[The Cobbler]

no name on the jack. I will use it for now and if it gets worse I'll tear into it & see what kind of damage I can do LOL

thanks for the help