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jfhollowayFlag for United States of America

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Ceramic brakes squeal

I have a 2001 Trans-am that I wanted to put new ceramic brakes and drilled amd slotted rotors on but the problem I am having is that when I replace the brakes with new ceramic brakepads they squeal whether I am on the brakes or not. The only time the car doesn't squeal is when I use the original factory rotors and new semi-metallic brake pads. This is the variations that I have tried but, the brakes always squeal. Have only tried replacing the front brakes. I don't even want to trink about trying the back until I get the front worked out.

I also tried the brake quiet stuff that goes on the back of the pads but, that didn't help either.

1. New drilled and slotted rotors with new ceramic brake pads - squeal
2. New drilled and slotted rotors with old brake pads - squeal
3. Factory rotors with new ceramic brake pads - squeal

They are prostop rotors and pads from Summit racing. I also tried platinum ceramic brakes from Advance Auto wi the same squeal results as the 3 listed above.

I bought a set of cheap ($21) semi-metallic pads from Advance Auto and used the factory rotors and they don't squeal at all but, the brake dust is horrible.

Does anyone have any idea why this is happening with ceramic brakes. And the original brake pads I took off were the factory original, Seriously they were. There is only 21k miles on the car.
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John
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I use standard rotors and semi metallic pads and (as for you) they work fine.

I do not know for sure, but since you get a squeal whether or not you apply the brakes, then I think it is high pitched air flow between the holes / slots and the pads. The air is probably escaping through whatever small passages it can.

I suggest you check with a mechanic familiar with your set up. It may be normal, or you may need to do something about the holes.
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Just making sure.   Did you install new pads and new rotors at the same time?  I had this issue before when I installed new pads on the worn rotors.  It was a slight rubbing noise because the old rotors have been worn in the shape of the old pads, and the new pads don't match them exactly. But they're perfectly safe, and the brakes will stop the car just the way they're supposed to with factory installed pads.
Some noise is normal especially while the pads are new.
Also in wet or humid conditions.

Once the brake pads have worn in after xxx miles the queal should go away.

"I also tried the brake quiet stuff that goes on the back of the pads but, that didn't help either."

That stuff does not last or work well.

You can insert Teflon-coated shims between the back of the pad and the brake piston.
Some pads came out of the box fitted with Teflon-coated shims already installed.
"1. New drilled and slotted rotors with new ceramic brake pads - squeal
2. New drilled and slotted rotors with old brake pads - squeal
3. Factory rotors with new ceramic brake pads - squeal"


Check that the rotors alignment is correct.

This video from Brake Align may be of help to understanding the importance of alignment.

 http://www.youtube.com/watch?v=SSxCNbjKi-0
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ASKER

Thanks everyone. The squeal sounds like metal to metal contact. I checked and can't find any place where there is metal to metal contact. To give idea of the niose, it sounds like when the wear indicator is rubbing the rotor. I verified that the wear indicator wasn't touching anywhere.

Tiras25, I replaced rotors and pads at the same time to start.
If the brakes work fine but the squeal bothers you then:
For real positive results, get the car tested on a dynamometer.
Just making sure, did you remove a preservative coating from the rotors before installing?

If yes, remove and file or sand the edge of the pads friction material - round off the corners of the pads.
Its like a teacher dragging her fingernails on the chalkboard.  If she's using a back of her nails the the noise goes away.  So file or grind the pads edges.  Then see what happens.
Re: previous comment:
 "remove and file or sand the edge of the pads friction material - round off the corners of the pads."

This may help reduce noise until the pads wear-in, but never round off the leading edge as the sheer edge is important to resist the entry of debris & water.

I suggest that you rough the new pads surface with 150 grit sandpaper to allow a faster wear-in period.
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Michael Best
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