I have a (possible) confession to make. It's lengthy, but please read it.
I have heretofore been advocating the use of copious quantities of anti- seize in certain locations during brake servicing in order to prevent corrosion and seizure of various parts.
Since the government banned asbestos as a friction material (~1995), I have had, off and on, problems with glaze on my rotors. Glaze is a smeary, patchy, durable black substance, which no solvent can dissolve. You can't even sand it off. The only way of getting rid of it is to machine the rotors.
Why was this happening? And why so intermittently? Over the last few years or so (I'm a slow learner...), I've been observing other people's brakes through the open-spoke wheels that are common these days, and have noticed that just about nobody has glaze, just lonely ol' me. Obviously it must be something I'm doing wrong.
Then, this last weekend (Mother's Day weekend), I decided to do my annual brake "spring cleaning". While pulling things apart, sanding, greasing, chopping, slicing, dicing and julienning, I noticed the rotors had glazed up, AGAIN! Something made me study the pads closely. To my surprise and alarm, I noticed the pads showed signs of oil seepage and absorption. The absorption areas closely coincided with the glaze on the rotors. The absorption areas also coincided with where I had been most lavish with the anti-seize grease. Worse, the rear disc brakes showed the same symptoms.
It appears on deeper investigation that anti-seizes of all kinds contain very light oils that creep readily when heated. And boy do they creep. This is only a theory right now, but I'm suspecting the oil soaks into the friction material, softening it so it smears on the rotors.
I replaced all the pads and rotors this spring with brand-new OEM. ($$$) The ONLY grease I put this time was under the pad slide shims, between them and the mount bracket, and sparingly, at that. And this time I used a high-temp silicone lube, Sil-Glyde.
In the fall of 2007, I'll see what the rotors look like and report back here.
If anybody has been following my advice had has also experienced rotor glaze, please let me know.
This page has been updated to reflect my new findings.