While there are kits of stainless steel parts, as well as a completely revised hinge system from Richard Winter in the UK, the old hinge assembly has probably just loosened up. First take a shot at tightening it up per the manual. If you find it's all rusted into one lump, and nothing turns, then worry about replacing it all. But if the nuts still turn, back everything off, apply Anti-Seize, and cinch it all up again.
The weather stripping pushes outward on the doors... especially the Twin Cam's bulb-seal type. That makes it difficult to press the door inward into position while working in the door to tighten up the hinge. So remove the weather stripping first, adjust the door, then replace the weather stripping.