A GM fix is a paid activity for the dealer and they could care less if it fixes your problem as the next visit under warranty is also paid, get the drift here? Plus they have had more than one "official" fix. You only need to be observant here not a mechanic. When you remove the top look for residue where surfaces have rubbed together or places that hard surfaces can come in contact during body flex. Use a proper weather seal lubricant such as a wax stick. Adjust the mount and lock downs to provide proper space between the chaffing parts. Note that there have been some end play in the clamp rollers that have created the problem. The fix will be simple when you find it and much easier than a trip to the dealer. Tip, cut a small piece of flexible plastic from a container, like a corn oil bottle, and put it in between the surfaces that may look like they are the problem when you replace your top and then it can be moved to find the actual offending spot.
As for the brakes there is and always has been a break in method for them. Most of the time on a new car that kind of instruction is ignored by the driver and most likely not even mentioned by the dealer. Simply put - No continuous hard braking for the first 1,000 miles. Used to be 4/500 miles but the harder pads need more bedding time. Break in is mentioned on page 2-19 of my owners manual but only for the first 200 miles, very optimistic. My guess would be that they did not "cut the rotors" as they have little material to spare. Best guess is that they cleaned glaze off the surface without cutting them. What that did for you was correct only a portion of the problem, the pads still have a glazed surface to make them screech. So in a short time the glaze is re-established on the rotor and it back to screeching all the time. I have cleaned both rotors and pads with an abrasive but you need a high pressure clean and then a solvent clean to make sure you don't leave any abrasive in the pads. Then bed them properly and the screeching is gone. I have never needed to install shims but now some ceramic pads do come with them already installed.
Only one GM vehicle has had a brake problem for me and I've owned my share of them. Under warranty I would take it back in and when I got it back it ran fine, for a while. Then the noise/vibration would return. I finally got tired of taking it to the dealer and remover the rotor that I thought was the problem. On the back side where it was out of sight there was an obvious hard spot in the cast rotor. That hard spot was the reason the brakes were glazing. I replaced the rotors and cleaned the pads, that was 3 years ago and I have had no more problems but am still amazed how smooth and quiet the brakes are (Power Slot). My cost $160 and no dealer headache, waiting on the service dept. or dropping it off and or listening to them tell me how I wasn't driving it right, geeze, get a life lady......
Yes, it would be nice if they would advise you of the proper way to drive on new brakes but it is much more profitable to just skip it and keep you ignorant of the procedure. Take a look...... http://www.tirerack.com/brakes/tech/techpage.jsp?techid=85
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<DIV><FONT face="Times New Roman">As for the brakes, did you break then in
properly? Most likely not, after all it's a $50K car and it can be driven
any old way the owner wants, right? My guess is that you have glazed the
pads by improper break in diving. Simple job to remove the glaze and then
break in your brakes properly. I'm nearing 40K miles on my C6 and
they are starting to show some wear but I have never heard a brake
squeal/squeak yet.</FONT></DIV></BLOCKQUOTE>I'm not a mechanic. I was not told
to do any "break in" or brakes. I've never done any break in of brakes on any
new car I've ever owned and no new car that I've owned ever squeaked this
much. If break in is required then the purchaser should be informed.
Additionally I took the car in and mentioned the problem. The dealer said they
"cut the rotors" and that helped - but only for a few weeks. At another
service appointment I mentioned it again and they were like "Well that's just
how they are some times and we can do a complete break job if you like". If
removal of the glaze and break in is required then shouldn't the service tech
perform that when informed of the problem?!?<BR>
<DIV class=moz-signature>-- <BR><A href="http://defaria.com ">Andrew
DeFaria</A><BR><SMALL><FONT color=#999999>Friends help you move. Real friends
help you move bodies.</FONT></SMALL> </DIV></BLOCKQUOTE></BODY></HTML>