I would clean off the rust and paint or use rust converter and paint before using bead sealer.

I had a '90 740 that was 7 years old and had bead sealer on the rims. When the tires started to leak air, my tire guy took one rim apart and found so much rust that he told me that the rims were dangerous.

They actually had rust 1/8 inch thick - this family shop that I have used since 1964 had never seen so much rust! BTW - I now deal with the grandsons.

I had to get 4 new rims.

Evidently the sealer sealed the rims but accelerated the rust