There is a way to get it apart. The threaded part that came off is held in by a small o-ring on the very end of it. To take the valve apart, you will need a soft set of jaws to hold the round part of the valve that the piece came out of. With this held in the vise, not too tight or it will become eggshaped and worthless, put a wrench on the square body of the valve and turn while carefully prying underneath to pull the two halves apart. They are only a press fit together. with those apart, you can dig out what's left of the retaining o-ring and then replace all the other o-rings while you are in there. Assemble the threaded piece in to the round half and install the retaining o-ring. You will then see how it's held together. When you are ready to assemble, smear a very small amount of 518 sealer around the male half of the two pieces, and then press back together.

Dave H.