My brakes have been making noises for a while, but it never bothered me till now. The pads aren't low and the rotors are good. It's making a noise like it's burning off all the rust from the surface after a rain or it's been sitting. They still stop great. I've noticed that the rear rotor is not perfectly smooth like the front after driving. It doesn't look pitted or chipped. I know the rears don't grab as hard as the front, but it looks like thay don't grab hard enough. All the cabin noise when stopping bothers me.

 

There could be a rock or something in the brakes??

 

Does it only make this noise when you are applying the brakes?????

And are you absolutely positive your front rotors are healthy. I know in my Mom's Bonneville, the front rotors looks ok from a glance, but when really inspected, they had all kinds of small stress cracks. Those little cracks were causing it to make a howling/ grinding type noise when braking. New pads and rotors fixed the issue.

Now if its happening all the time, even when you are not breaking, it sorta sounds like a bad wheel bearing (from the noise you are describing). But like I said, thats only if you are hearing it ALL the time.