I have a 1995 bronco(full size)4x4.When I apply the brakes it sounds like metal to metal grinding. Brakes? Thats what I thought it was.Took it to a brake shop and they said the brakes were fine.When I come to a slow stop from 10-20 mph is when I hear the grinding noise.When I come to a stop from 40-50mph, no grinding noise.When I hear the grinding noise I can back up and then go forward and come to a stop,no noise.I took my truck to one shop and the guy said it was the harmonic balancer?I'm not a mechanic,but how can the H.B.be causing a noise in the right front wheel?Another guy said it was the air pump??I need someone who knows what there doing,not a parts replacer.