I installed a new self bailer but even after filing flat the peak on the underside to get a good seal to the o-ring it still leaked. There was some delamination between the top of the tube and the deck.
Rather than trying to replace the tube I filled the hole with epoxy and silica filler. Just tape the bottom of the hole and pour it in. Mine will probably stay that way but I could now easily re drill the hole and the leaks between the tube and deck should be sealed.
George