If you've ever wondered why Mavericks & Comets rust so badly...I think it has a little to do with the over use of sealer at the factory...look at this gob of stuff, inside the door. It was right behind the two bigger cut outs...
I've found large wads of that stuff everywhere. I removed every bit of it and have been replacing it with more modern sealer as I go
Helps to prevents moisture from getting into a seam between metal pieces and causing corrosion - I think it might also prevent some squeaks in the car
I've used a grey brushable seam sealer sold by Eastwood - it comes in a quart can - it has worked well for replacing the goop. I buy cheap brushes from Harbor Frieght and throw them away when I'm finished. The way I figure it is no one had the the time to be neat on an assembly line in the 70's so Ford has these goop guns shooting this stuff on by the gallons - now is the time to re-do it the right way
I've already rust bullet and painted over some of my seams I removed it from.... Worth stripping it down to seal, or just know for the future?
Actually Rust Bullet can seal up a seam like concrete It will glue your fingers together but, in the long run, it isn't going to be very plyable like a seam sealer would be - I would try scuffing up the paint around the seam so the sealer sticks, apply the sealer and just repaint that area