Umm I had a CPS 1000 that was missing the pump, I guess you could walk into a hardware store with THAT and ask for help?
What would be nice is a bolt, with two large washers and one smaller diameter washer the same thickness as an o-ring, then you can sandwich the smaller washer and o-ring between the other two. Thread/glue that bolt into a piece of pipe and you're done. In theory.
In practice you start with an o ring, and then from there find a way to secure it on a pipe between two things that won't slide and won't let the o ring come off unless you pull the pump out.