Reading this with interest. I am halfway through replacing the diaphragms on my boat at the moment. Admittedly it is a Yanmar engine and saildrive with their double diaphragm arrangement. I undertook this project as we found that one of the diaphragm clamps was missing – so someone has been in there at some point. No record of the work ever having been done so on a 1999 boat bit the bullet and got stuck in. Saildrive currently in pieces in the garage and just about to rebuild and re-attach to engine. Waiting for the prop shaft to come back as it had to go off to engineers to be re-chromed and then ground back down to remove oil-seal wear grooves. Replacing all associated seals diaphragms etc etc. Myself and wife got it out ourselves and will put it back in ourselves, bit of a wiggle but it will fit!!
Of course, relevant to the thread….the diaphragms that came off the leg looked like the new ones, no sign of wear or age. I keep telling myself that at least I can sleep more soundly. The Yanmar parts have no date marking, or markings at all, but we keep full records of work done and parts replaced. Should all be back together in week or so when the weather allows.
B38, Alcyone of Argyll