anasazi

i installed the C5 brakes with the z06 pads.

everything has been good, i broke them in by driving nicely and not using the brakes hard for a good week.

the brakes have been silent until the past week or so, and now when they warm up they squeel like crazy!

what can i do to correct this?

lateapex

You are probably building up brake pad material on your rotors. Those pads like to see some high-temp, heavy use now and then.

Find a non-public road where you can safely make 3 maximum deceleration back-to-back stops from about 60 mph. If you don’t ever invoke ABS, then this would be a good time to cycle some fresh brake fluid through the ABS system by activating it, just lightly.

Have your window down so you can smell the brakes. By the end of the third stop, you should have cleaned all of the excess pad material off of your rotors, and helped the long-term life of your ABS system. You should also smell the brakes a little. If you don’t clean the excess material off of your rotors, it will continue to build up to the point that you will start to feel a slight pulsing in the brake pedal, like mildly warped rotors.

If you are not ever going to really use the brakes hard, you might consider going to a pure street pad at your first pad replacement. You may not be able to convert to SOME ceramic based pads on those rotors because they have been bedded with carbon/metallic pads. The Hawk HPS’s should be compatible, will provide much of the “bite” of the ZO6 pads, and are more appropriate for mild street driving.

anasazi

well we went out on some roads tonight and when no one was within a few miles behind us we hit the brakes HARD from about 80mph to nearly stopped, 3 times ...

and it still squeels

did it 3 more times on a different road and it squeels even after that

we definantly heated it up, could smell the brakes real good after that third stop.

what else might i do to correct this squeel?

lateapex

I have recommended this fix to many people, and you are the first that reported failure. You may have let it go on too long before removing the buildup. See: http://www.stoptech.com/faq/data/faq25.htm and http://www.stoptech.com/whitepapers/...otors_myth.htm . When they refer to vibration or pulsing in the pedal, this is a different manifestation of what you are experiencing. Your vibration is just higher in frequency, and lower in magnitude. Even though they are pessimistic about your being able to save the rotors at that point, your rotors have not gotten that bad yet (if you feel no pulsing). If you could borrow some C5 pads that were harder (higher temp track pads), that would probably work at this point. The other cure would be to use some 220 grit garnet paper and try to break through the deposits (you probably won’t be able to see them yet).

If you read the above papers, you know at some point that the deposits get thick enough to cause additional heating to the rotor surface directly below the deposit. At that point, the rotors are toast. If you haven’t really been leaning hard on your breaks for a long time, the rotors are still salvageable. If you try the garnet paper, use it on a completely flat sanding block, and create a cross-hatch pattern; do not sand circumferentially. If you do sand, you will need to re-season the rotors and re-bed the pads. Follow Baer’s instructions this time.

Is the squeal at all cyclic? I mean, just before the car stops, does the volume or pitch of the noise vary in sync with each revolution of the wheel? Or, do you feel ANY vibration? It would really help if I knew if you are a very light brake user, or a racer, or what. I assume from your location that you are not doing a lot of mountain driving. Is there any blue tint to your rotors? The more information you give, the easier it is to narrow down your problem.

There is always the possibility that you are experiencing a more conventional brake noise. To cure normal brake squeal, make sure that the caliper guide pins are well lubricated with silicone brake grease. Inspect the pads, and if they came with silencing shims, verify that they are still properly in place. They often shift around and get jammed-up around the edge of the pads. If that is the case, then remove them. Try an anti-squeal coating on the back of the pads in place of the metal shims. Well, if you are just having normal brake squeal, do a Google search on “brake squeal” and you will get lots of suggestions.