Other than the final repair looking a little "redneck" there's nothing at all wrong with using a rubber expansion plug as a replacement in tight quarters. Install it "dry" and tighten it well- - - -sealer will just lubricate it as it pops out. Anyone who is critical of that procedure is welcome to show me how he would do it- - - -I'll watch and learn!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!