There seems to be some confusion about the materials. From the Ertalyte web site, it is most definitely NOT NYLON "Ertalyte® is an unreinforced, semi-crystalline thermoplastic polyester based on polyethylene terephthalate (PET-P)." it is a variation on PET, the material that soda bottles and polyfleece vests are made of.
Instead of packing the bearing with vinegar, pour in alcohol (any kind, highest proof you can) and then add in a slurry of dry ice chips. The alcohol conducts the cold without freezing, so you'll REALLY cold-shrink those parts.
You could so the same thing by applying a CO2 extinguisher--but the dry ice chips will be way cheaper and less fuss.
Usual precautions that dry ice disagress with eyes, flesh, etc. and high test alcohol vapors do all that and catch fire if you're smoking.
You might try calling the folks at Kroil or PBlaster and asking if their products will attack a calcium-aluminum problem, they're not just lubrications, they chemically break corrosion problems.
The whole thing still sounds odd, I'd expect calcified anything to basically act like sand and abrade down any type of plastic bearing material, rather than lock it up. Whatever you rebuild with, you might consider packing the bearing area with Dupont Krytox grease. Kyrtox is expensive, but chemically inert, even in a pure sulpur or chlorine or oxygen environment. It is thermally stable from -70F to 700F, and doesn't migrate. Has no effect on rubber, plastics, or petrochemical seals or parts, so it should lube your new bearings as well or better than anything else on the planet, or at least, longer than anything else. And of course, it will smother any algae that enter the rudder tube.