John Deere 950 with yanmar 3cyl.
Mine doubles as a weed sprayer at the moment. Tried torqueing it a bit with no luck. Pretty sure thing just needs replaced. It's approximately somewhere between 3/4" and 1" OD by eye. Haven't fished it out of it's groove yet to measure. Figured I'd try to find one before taking it out in case the majority on a forum tells me I was just not holding my mouth right, or doing something wrong. It's just resting there apart right now waiting.
My local parts guy is a very small business, mainly just lawn mower sells. He lacks the proper tech books to offer me a part number. I'm sure it's SAE material and most likely some JD-odd size. So I'm not just going to accept anything other than a certified o-ring for the specification. I don't think I can just take it to any parts store to buy the same. I've fought that battle with other hydraulic equipment in the past.
Any help would be MUCH much appreciated. I kinda like to do things one time although it rarely goes that way... :-)