The left door mirror on my 80 needs repair. The rubber which held the mirror in place tighten has over the years shrunken and harden. The mirror is still in place, but is loose, rattles, and effectively useless to use at lower speeds. It's the reflection surface that is loose. Mirror mount itself is fine.
Is there a good fix other than replacing the mirror, or shimming the gap with something.
Air pressure holds the mirror in place quite well at 70mph and above.