+1 on the bed-it butyl tape! Our
Morgan 28 has 1/4" s/s bolts through the aluminum T-track, through a
teak toerail then finally through the
fiberglass deck. We removed them a few years ago in order to resolve
leaks into the quarterberths. We like the butyl rubber because it allows some movement without breaking the seal.
Following Mainesail's
advice, we put a little string of butyl tape under the
head of each bolt before inserting it into the T-track, then held the
head of the bolt still while tightening the nut from below to keep the butyl from twisting out. A strip of tape between the
teak and the deck insures nothing gets inside.
BTW, is that pic from your T-track? We saw no corrosion at all when we disassembled ours and it had been leaking water for years...