Hi all,
I just replaced the front rotors on my 1990 Miata. The pads still had a lot of meat on them, so I reused them. After putting it back together and going for a drive, I heard a metal on metal grinding sound. I looked at the rotors and noticed that they are now scored. It looks like the metal cage that wraps around the rotor (the bracket that is bolted to the hub, which hold the pads) is contacting the rotor surface. I'm wondering if the new rotors are so thick that they are contacting this bracket, of if I have something out of alignment. Any thoughts?
Thanks,
Mark
Wait, are they touching the rotor backing plate, or the caliper bracket? It is easy to accidentally tweak the backing plate as the metal is real thin, but unless you bent something real, real bad, they definitely shouldn't be touching the caliper bracket.
Also your old pads were probably wear-matched to the old rotors to some extent. You will probably be fine but unevenly worn pads on brand new rotors can initially do weird stuff too. This might be a part of your issue, at least until the pads re-seat.
Sounds more like the caliper bracket is touching the rotor, in which case, WTF!? That's something that should only happen if you have totally wrong rotors installed.
I don't see how the bracket is touching the rotor, unless it's the WAY wrong rotor, or you didn't install the pads? Heck, a friend called me the other day, said that he had a similar sound, but he threw the pads in backwards when he rushed the job. Flipping the pads made it all better. Can you post some close up pictures?
'90-'93 Miata rotors are smaller than '94+. Are you 100% sure you were sold the correct (little) rotors?
So, in other words, you got the wrong parts.
I can't think of a creative installation that would put the correct rotors in contact with the caliper bracket.
Thanks for everyone's feedback. I figured out what the issue was. I took the new rotors off the car and measured them against the old ones. The top hats on the new rotors are about 2mm shorter than the top hats on the old rotors. With the shorter top hat, the outer friction face is now 2mm further outboard than the old rotors. This was enough for the face to make contact with the caliper bracket. The 2mm was a small enough difference that I didn't notice it by eye when swapping them. That's what I get for buying the cheap store-brand rotors.
