The infamous "dip tube problem" involved heaters manufactured roughly between 1992-1996, so the problem was not known to exist back in 1984. It also seems unlikely that debris could be lingering in your pipes for such a long time.

This will require some detective work to rule out :
a. something from your water supply (city or well).

b. something from your main line coming into the house ( is it copper, galv., PB, PE, PVC, etc?

c. some component in your house (piping, faucets, fittings, etc).

Good luck. Some calls to professionals who work in your area would help; maybe someone else has had this problem.