Folding Tongue Stuck
I'm not sure if drilling a couple relief holes in the outer part so you can inject some PB Blaster is a good idea structurally but some how you need to get some penetrating oil in there to loosen things up
I just did the Reliable to UFP retrofit and I made sure to put some highly water resistant marine wheel bearing grease inside the sleeve and on the bolt
It's a near zero tolerance on mine and I could see how some rust could make things difficult but you would think a half inch impact wrench would budge it a little
I wonder if a propane torch would help or have you already tried that?? Sure hate to mess the paint up though!