I have a 300 Sherwood, Martini action, and a Bland 303 double, both of which have folding rear sight leaves. They are not spring loaded, and flop up with just an inversion of the rifle. The pins have been replaced, and that worked for the first couple of times, but now they flop! These are very simple types, with 2 leaves per pin, one with a center bearing, the next with two bearing tubes outside the first.

Any advise on how to fix the floppies would be appreciated!! Possibly squeeze the base at the pin hole? Fill it full of rubber cement? I'm kinda out of ideas, so help would be good, before I do fill it up with rubber!
Thanks, Doug