I have an '87. IIRC, there should be two springs inside the hub holding the shoes together, and another one on the brake petal. Most likely, the pivots for the brake shoes and the petal are gunked up. They get pretty nasty and build up a sticky tar like goop. I bet if pull them apart, clean, and re grease, they should be good for another 20 years

Check the shoes and drum surface as well...if it has been hanging up for a long time it may have gotten really hot and warped the hub and trashed the springs.