Bota,
Shoot!!! If I'd known, I'd a taken a photo of my check valve yesterday. Just pulled it out, took it apart, cleaned it, put it back.
Yes, there was a o-ring like gasket sitting on the inner ledge of one of the pieces, made of brass I think, that helped seal the unit. Although I "[censored]-punched both halves before dissasembling, both halves were slightly warped in such a way that it would only go back happily the way it was.
The only other part, other than the two halves, 4 screws, and o-ring, is the "stopper" valve itself. Shaped kinda like a kid's spinny top. Rubber face on the side that seals.
After I cleaned it and reassembled, I could test it with my mouth. Sucking one side worked, sucking the other gets nothing, just like it should.
Does this help?
-Michael
