As I was finishing the front end on my 70 Dart GT, I completely rebuilt the factory KH brakes. That included rotors made by Centric that I got from Rock Auto. All new front end parts, rebuilt, and on one side, replaced hubs, with fresh bearings and seals, new rotors, new calipers, all new hard and soft lines, new distribution and proportioning valves. As I started to drive the car around the brakes felt and worked fine, but I had two problems: the dash brake light was on all the time (not related to the emergency brake system) and goes out when you push hard on the brakes, and starting at 35mph there was an annoying, persistent high pitched squeal. There was a bit of vibration when the brakes were applied, but not anything worrisome.
As has been described here many times, the edge of the piston boots on the caliper just barely hit the side of the 'hat' of the rotor. Having tried everything I could think of, I took it to a friend's repair shop where they have a brake lathe. I had them turn down the side of the hat just a bit to clear the boots. While the rotor was in the lathe, he put a dial indicator on the face of the disc. One rotor had a .010 dip in it, and the other had a .006 dip. He surfaced the discs and we put it all back together. No squeal and even the minimal vibration in the pedal was completely gone. Brakes work better than ever.
As I recall those rotors were quite inexpensive compared to lots of the parts I bought and I can't think of anything on the car that is more important than brakes. My suggestion is this: if you are using those rotors, mock them up to confirm if the boots hit the hat. If they do have then turned down and have the discs checked as true before moving forward. When you add what I paid for the rotors and for the machine work, it's just not worth it not to do it right as a part of the rebuild.
While the car was in the shop they vacuum bled the brakes (they had been hand bled twice), and whatever made the difference, the light comes on when you turn on the car, but just a bit of pedal pressure turns it out. I presume that the new distribution valve from In-Line Tube is faulty, so my next try is to send the original valve to a place that rebuilds them and swap them out. Other suggestions?
As has been described here many times, the edge of the piston boots on the caliper just barely hit the side of the 'hat' of the rotor. Having tried everything I could think of, I took it to a friend's repair shop where they have a brake lathe. I had them turn down the side of the hat just a bit to clear the boots. While the rotor was in the lathe, he put a dial indicator on the face of the disc. One rotor had a .010 dip in it, and the other had a .006 dip. He surfaced the discs and we put it all back together. No squeal and even the minimal vibration in the pedal was completely gone. Brakes work better than ever.
As I recall those rotors were quite inexpensive compared to lots of the parts I bought and I can't think of anything on the car that is more important than brakes. My suggestion is this: if you are using those rotors, mock them up to confirm if the boots hit the hat. If they do have then turned down and have the discs checked as true before moving forward. When you add what I paid for the rotors and for the machine work, it's just not worth it not to do it right as a part of the rebuild.
While the car was in the shop they vacuum bled the brakes (they had been hand bled twice), and whatever made the difference, the light comes on when you turn on the car, but just a bit of pedal pressure turns it out. I presume that the new distribution valve from In-Line Tube is faulty, so my next try is to send the original valve to a place that rebuilds them and swap them out. Other suggestions?
