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Originally Posted by copdocpvd
Came back next day, their "fix" was to turn the rotors and burnish the OEM pads (which had a ton of pad material left), which they listed on the service sheet as "de-glazing."
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The pads had glaze for a couple of reasons. See my comments below
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I said "you mean, brake gently to warm up the disks so as not to shock the pads and disks, then bring the car to 60 mph, brake as hard as I can, just shy of activating the ABS, all the way to just before full stop, then accellerate again, until the brakes cool down again, and repeat that about eight times, then do it at 80 MPH? Yeah, I did that, and even threw in four runs at 100mph, being absolutely certain that the brakes were completely cool before coming to a full stop so as not to risk 'burning' brake pad material onto the hot disks which can cause noise and reduce braking effectiveness."
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What you've done here is to combine the bedding for street pads with bedding for full race pads. It's not a case of if some is good, then more must be better. By doing the bedding at 80mph, then adding four runs at 100mph, you completely cooked those street pads. A layer of glaze formed on them and, since you don't have slotted rotors, it remained - causing the squeal at light pedal pressure and should have reduced your friction level somewhat.
Keep in mind that the energy you put into your brakes goes up with the square of the velocity. So an 80mph stop is not a 33% increase in energy over a 60mph stop. It's a 75% increase. And a 100mph stop is not a 66% increase, it is a 178% increase. (If I did the math right.)
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Then I told him for the fifth time, "I really do NOT think this is a brake pad issue, my friend, I know a tiny bit about what I am talking about."
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In this case, it was a pad issue.
After they deglazed the pads and turned the rotors, it became a pad & rotor issue. You've essentially gone back to square one. There is no pad transfer layer on the rotors, after they've been machined. So you need to rebed the brakes, this time only doing a series of near stops from 60mph (per:
http://www.zeckhausen.com/bedding_in_brakes.htm). If the pads haven't been ruined from the abuse earlier, this should cure the noise. If it does not, then you should replace the pads.