Oh, is this that Zenith you just got on Ebay? I would say that if the problem is that infrequent, and doesn't bother you so much, just let it go. Wholesale recapping of radios just because of their age is a controversial practice, though it's usually the first thing I consider if the radio shows signs of more serious malfunction. Just keep threatening to tear into 'er, and she should stay pretty well in line.
Paula