Several sealants are needed here
I have a 1955 Chevy Bel Air 2-door post. The back seat window tracks have several screws that secure it to the inside of the car. The screws are covered with something that looks somewhat like plumber’s putty. This keeps water out and can be removed to remove the screws. What can be used to replace this putty?
There is one large and one small metal cover plate on the inside of the car that can be removed to access the window tracks. Both of them are sealed with something that looks like roofing tar. What can be used for this? Inside this area can be seen the rear wheel tub and the outer quarter skin. There is some type of rubber between the wheel tub and outer skin with a layer of some type of hard sealer. The outer skin is no longer secured to the tub and I need something to secure it and seal the seam.
I do not think I can remove all of the old sealer due to limited access, and it is very hard like the sealer used on the two metal plates. What can be used? Also in this area is some sound deadening material that has peeled away with light surface rust inside this area. I can think of several directions to go but what is best for this limited access area?
To replace the putty around screws I would use white silicone sealer. Also, the sealer you mentioned that looks like roofing tar is probably chassis undercoating, which is available in cans from auto parts stores. The sealer in the wheel tub would best be replaced with black silicone sealer. And the best thing I know of to protect against rust in hard-to-reach areas is cavity wax, which is available from automotive paint stores.
To spray on cavity wax you will need a special wand that lets you rotate the nozzle, and you will need to hook it up to a compressor. You can then just push the wand into any area you want to seal and spray the wax all over the surfaces. You don’t have to get fancy. Nobody is going to see your work. I just spray it on and in every inside panel and crevice until it runs out the bottom. Just make sure any drain holes in doors are open to let water out. Cavity was is flexible, and seals against moisture very effectively.