Liebherr ltm 1080/1 I've got steering cylinders that are seeping, and I'm going to have to reseal some of them- probably end up sealing all of them. I did one a year and half ago, and in resealing, I messed up one of the teflon rings. (teflon rings are a pain to install) The seal kits are really $$$ from liebherr, so instead of trying again with another seal kit, I replaced the cylinder to get the crane back up and running. Now I'm looking at doing several more, and I don't want to replace all those cylinders. My hydraulic shop can get me the o-rings and teflon rings that I need, but on the gland end, they use a "buffer" o ring and teflon seal in one groove, and then they have a one piece wiper and u cup seal. The one piece wiper/ ucup seal is the one they can't find. We looked at replacing the oring and teflon buffer with a ucup seal, and then put another u cup where the one piece seal and wiper is as a wiper, but I don't really want to remove the buffer (afraid of steering shock and rod damage). Or have contamination with no wiper. The seal kits are around $200, and the new cylinder was over $900. Its only 3 orings, two teflon rings, two wear bands, and a ucup seal and wiper combo. So if I can get the combo ucup/ wiper, I'm going to be in good shape to reseal the rest of the cylinders as needed. Its $70 for the rest of the seals. The dimensions on the seal are 25x35x5 and its a combination seal and wiper all in one. Someone is making this seal, I just need to find out who. It may be a captured part, which wouldn't surprise me with liebherr. Any advice for installing the teflon rings with less trouble would also be appreciated. Last time I dropped them in my hyd. oil filled crock pot for a warm up, and a lubed install, but it wasn't any fun.
That used to be called a polypak. They worked good for replacing old chevron packing but the pressure range was around 2,500 max. It should still work fine for a wiper though. The teflon rings are always a pain but nothing else works as well. Those work in the 3K to 5K pressure ranges.
Boil the teflon rings in water for about five minutes, pull out with a wire hook or needle nose, shake the water off and immediately with gloved hands attempt install. Bobcat used to use those on all their cylinders.
So the oring under the teflon ring is actually doing the pressure fluid sealing, and the ucup/with wiper made in, is really just acting like a wiper? The hyd. guys today acted like the oring and teflon was just a buffer to take away shock load/ slow it down, and the cup seal with wiper was doing the sealing. They were having trouble sourcing the ucup/wiper seal, and if its not doing the main sealing, maybe I can use just a standard "polypak"/ ucup seal there. I looked at the poly paks I could find on the internet, and didn't find any with the made in wiper like mine, some of the pnuematic seals have that, but I didn't spot any for hyd. uses. The search goes on. Thanks for the help guys.
No, the O-ring just supplies tension like a spring to load the teflon ring, though of course it does seal itself in the groove. I would bet that little green guy actually does all the sealing since it's loaded with an O-ring. Weird little seal. You say it's 25x35x5, is 5mm the total height?
5mm is height.
Would it be feasible to have a new gland made that would accept readily available seals on it ?
I kinda doubt that would be $$$ ahead. I'm looking at less than $100 if I can find the seals local, liebherr can get me a seal kit for around $200. There's 6 or 8 of those cylinders, so I was just trying to save a few $$$. I don't see getting new glands made for less than $100. If it was $100 to have the glands made, I'm at $200 total with new seals, I just as well buy the liebherr kits and be done with it.
I searched up and down the internet for that seal closest I found is out of stock in the UK its an interesting set up why they used a buffer in there which would reduce pressure to protect the U seal out front thing is if the pressure is that high that they need a buffer why wouldn't there be another rod seal as any real pressure would shove the snap in wiper out and if the pressure is low why mess with a buffer and special wiper when a regular rod seal and wiper would do Best bet is to pony up the 200 and be all set if they were not available or not such a critical part it would make sense to refit them a lot of downtime it they started leaking again
https://herculesus.com/page.php?name=Download-Catalog-PDFs&id=311 Down load a catalog, if they don't have it it ain't made. And they can make seals too. Joe H