G-Sep

Hey guys, not sure if this has been covered, been searching on and off for a little while and can't seem to find it.

I've been cleaning out engine parts in prep for assembling an sr. While I was cleaning the oil block I noticed that small gray seal (it's towards the right of the block) was in the hole with the spring (bottom center) all loose. So I removed the large bolt, spring and ball and the seal came out, looking kind of mangled.

My question: Where exactly does this seal go? And, can I buy a replacement for it?

Thanks