Rattling brakes 76 Duster

I have a 76 Duster with basic stock disc brakes and it has a annoying rattle coming from the front end that quits when the brakes are applied even slightly.This is the second Duster I've owned and both had the same rattle and I haven't figured it out in over 20 years.
I'm trying to sell this car and prospective buyers are scared off because they think the front end it shot(no,thats not it).Any help would be appricated-Rag