2001 Chrysler PT Cruiser Noise that comes and goes

I have a PT that makes a humming or rubbing noise. Sounds like it's coming from the rear. When the car is turned on it takes a while before I hear it, 8-10 miles. It stops when I hit the breaks, but usually starts again, it comes and goes. It can be a low back ground noise or can get very loud. Can be loud outside of the car. It's worse when it's damp or wet. When the car is turned off and turned right back on it does't always start back. I've had the breaks torn apart twice and they do find even ware, but say I don't need breaks yet.