LOUD grinding noise coming from rear

[typeshluder]

This is the second time it happened. This time, I was on the highway pulling up to a toll booth when an extremely loud metal on metal grinding noise started. It went away within 30 seconds. Not sure if it was the brakes or what but it was LOUD! It's an 08.5 MS3 with 3,100 miles. Any ideas what it could be? Any recalls I should know about?

 

[Kain]

Were you braking when the noise occured? If so, check your calipers/pads. Look under and see if the nuts on the end links that mount to the rear sway bar have come loose or are missing, too.

 

[derspi]

Could have gotten a small rock or pebble lodged between the caliper and rotor. Had something similar happen to me but the grinding noise was from the front.

 

[DaleNixon]

+1 on the endlinks. Mine keep coming loose. I'm about to red loctite those bastids.