Auto Parts: chevy, chevy cobalt, grit sandpaper

Question
i have a 2007 chevy cobalt LS. When i let go of my break, i find this squeaky noise. i went into the shop they said its the calipers.. it was DEFINETLY not the calipers. I can be going 5km/h step on my break and as i'm releasing, its squeaking, and ideas??

Answer
    If you only get this noise when releasing the brake, and it is not coming from outside the car, then you may have a leak in your vacuum booster.  However, unless you have been literally driving the wheels off of this 2-year-old car, this is extremely unlikely.  If the noise is coming from outside, it probably is the caliper.  Not that the caliper is malfunctioning, but just squeaking.  I have had several cars that would squeak when just releasing the brake to go forward, or just as the car came to a stop under very light braking force; and one of them was a Mercedes.  Having the thickness of the pads checked is a good idea.  But, if they are plenty thick, you really do have a problem if you can't stand the squeaking.  I used to rock the car back and forth with the brake at stoplights and play a little tune of sorts with the squeaking noise, but not everyone would want to be able to do that.  To get rid of the squeak you should (after checking on how it affects your warranty--the dealer really should be willing to do this all for free and, if they won't, I'd complain directly to GM while they're still in business) disassemble the caliper from the rotor, remove the rotor from the car and, using a disc sander and 400 grit sandpaper, sand both sides of the rotor until they are no longer shiny.  Then pull the pads from the caliper and lightly sand the surface where they contact the rotor with the same paper, but by hand.  Go to the parts store first and buy some shims for the pads and a tube of caliper grease.  Apply the grease very sparingly to any part of the caliper assembly where metal touches metal.  Put the new shims behind the pads and reassemble the whole thing.  This will eliminate any squealing or squeaking on any car.