To keep from pulling your hair out, you could just do a really neat job of taping up the rubber parts and hitting it with some rattle can. Of course, after prepping the surface with scotchbrite and some Grease & Wax remover. I don't think that this would be a problem at all. It may not be completely necessary to remove the rod and inner flap anyway. Most of the time what rusts is the plate between there and the firewall. I have a complete heater box at home that is eat out on the bottom of that metal panel. I lucked up and had a friend, that changed to Vintage Air, give me his old heater box that was in great condition. I put mine and the other one I had in a box and stored it away and used the good one. I still disassembled the box and painted everything and installed with new rubber/gaskets. You'll get it. Keep moving on it and don't let it whip ya!
