Hey guys, just got done putting new rear rotors on my 94 SC300 and now it seems the rear driver's side (not sure about the passenger side) is scraping all the time at any speed without any braking. I replaced only the rear rotors, not the pads as those looked okay and still useable. I replaced my rear rotors only cause they appeared warped and the car would shake violently when braking from higher speeds. The front rotors/pads are in great shape from what I can tell. Anyway, I didn't compress the caliper pistons in the back cause I just reused the old pads that I already had. Should I have compressed the pistons even though I reused the old pads that are still good? Does it make a difference? The pads fit tightly around the rotor when I put the caliper back on, I thought that pumping the brakes when I started the car would put them in the right place. The dust shield isn't scraping, I already checked. It also looks as if something is leaving circular scrapes against the face of the rotor where the pads make contacts. It sounds horrible. Can anyone please give me some help! Thanks.

Oh btw, can't be a seized caliper either, had those replaced not too long ago.

 

I think that might be normal. With new rotors, your brake pad's will get used to the rotor by wearing down. My Dad's Mazda Miata had that after replacing the front rotors and the eventually evened out. That's just what I think though.
(If it isn't that, maybe you didn't push the rotor into the place it was supposed to go?) (A "REALLY" tiny maybe. )

 

Yeah I only drove the car like literally to the end of my street (about a 50 yards), got nervous cause of the noise and turned right back around and parked the car. So should I keep driving it and see if it fixes itself? Somehow I don't think thats a good idea...

 

I would suggest taking the caliper off and compressing the pistons and starting from there. The new rotors may have a good amount more meat, causing the pads to be too tight even though you didnt replace them. I would guess the brakes are too tight, but maybe pumping the brakes with the reservoir open would help.

 

I'm not to sure of the term but there are two guides on the outer ends of the caliper. I know that the guide closest to the ground has a tendency to seize up due to weather erosion . Maybe see if their free and not locked up. The piston can still move back and forth but the guides could be the source of the rubbing if they are locked up.

 

Well, I said it sounded normal. It won't need to fix itself, they just have to get used to the new [larger] rotors make sure the brakes still are functional of course.

 

Yeah I guess I'll try to compress the pistons and put the pads back in, I got new pads today anyway guess I might as well put those in there instead for the new rotors.

 

I never recommend reusing the old pads on the new rotors. The pads will wear to the rotor when replaced together, when you mismatch, the new rotors will not wear properly due to the old pads. Put new pads on and double check your work.

 

Yeah, so a little update, I ended up compressing the calipers and putting the new pads in with the brake reservoir open, started the car, pumped the brakes a few times and then took it for a spin. It made the same noise but after driving up and down the street and adjusting the dust shield a few times, the noise went away. Guess the new pads had to wear down a bit before the noise would stop.