Thanks. It’s all torn apart now, tank off the airplane, and I suspect fuel’s been leaking around the outflow hardware, based on some slight corrosion (from accumulated water in fuel) and absence of much sealant on the threads. Original bladder looks pretty good. The original drain mast must’ve broken off at some point and a poorly fabricated one grafted on. Leaked fuel helped debond the fiberglass patch holding the drain on. We’ve fabricated a much better replacement drain. Will bond that on, reassemble, and leak check before reinstalling.

Larry Ruggiero