O ring

[wbvs58]

I have just pulled apart a leaky hydraulic cylinder from the loader on an older Kubota tractor I have recently purchased. The cylinder has been leaking from the joint between the cap and the cylinder (quiet a lot actually). On pulling it down, I found an O ring and a flat skinny ring in the same groove, the skinny ring was creased and folded over contributing to the leak.
Is it normal to have these two rings in the one groove, or has someone added the second because they didn't have one the right thickness and tried to bodgie it up? The cylinder has obvious marks on it where someone has pulled it down previously. It was not leaking around the shaft.
Any help or suggestions would be appreciated. Thanks.
Ken

 

[RickB]

One or two backup rings next to an o-ring in a cylinder piston or gland is normal and more common than not. If only one is used on the gland, it ALWAYS goes on the side of the o-ring away from the oil.

 

[wbvs58]

Thanks for that Rick, I can go shopping in town for parts tomorrow.
Ken

 

[wbvs58]

I picked up the rings today, got them for nothing actually, the woman couldn't find them on the computer so she said just take them, so I did. I took a lot of care to make sure they sat in the groove and watched closely to make sure I did not pinch them when screwing the cap back on. Got it all back together and then tested it, no leaks, so thanks for the help.
Ken

 

[DiskDoctr]

I picked up the rings today, got them for nothing actually, the woman couldn't find them on the computer so she said just take them, so I did. I took a lot of care to make sure they sat in the groove and watched closely to make sure I did not pinch them when screwing the cap back on. Got it all back together and then tested it, no leaks, so thanks for the help.
Ken

Ken,

Keep an eye on it. If you can dig up a drawing on your tractor and find the exploded diagram for your cylinder, you may be surprised to find 6-10 parts that seal your cylinder. Repacking/rebuild and seal kits are terms I've used to order the replacement parts.

If one of the internal seals or bands are cracked (common), high pressure fluid can bypass and eventually push past the outer seals, like the oring I believe you are describing. It can twist or tear the oring, which doesn't really hold pressure, just seals the tube.

If you do end up rebuilding the cylinder, a digital camera is a MUST HAVE, IMHO, to remember the exact order and locations in which to re-assemble the new kit. Seems like we always end up with a week or so waiting for parts, so the little bit of memory I do have fades....

So keep an eye out and don't be alarmed if it leaks again. Just means you need to use the whole kit. We've never been lucky enough to escape with just an outer oring. Once inside, we were glad we did the whole kit, but it's still a PIA

The first one you do seems overwhelming. After that...not so bad.

- JC