Left my car parked outside in the Boston winter for about 6 weeks. Just drove it for the first time yesterday - am getting grinding noises and a thumping noise from the rear brakes. Figured the grinding and slight pulsation in the brake pedal is due to rust on the rotors (which should wear off over time) but what is the thumping noise at slow speeds and on braking? Will this go away on its own?

 

Snow/ice buildiup?

 

Drove it for about 60 miles over the weekend, mainly city driving. Noise is pretty much gone now. I think it was due to rust on the rotors that wore off with normal braking...

 

That noise (but not thump) happens to me when I drive the car after a rainy night. Just a little water on the rotors allows rust.

 

I think you're right. Leaving a car parked for an extended period in wet weather will cause the rotors to rust unevenly (some areas open, some close to pads). My MINI doesn't do this too badly, but my VW does. A few dozen stops usually smoothes everything back out and the system is quiet again.

 

^^^ We have a winner, rusty rotors for sure.