Rattle in rear end (SOLVED)

A little history:

I have a 2011 M3 convertible that has had a rattle in the rear end that has came and gone. My dealer, along with factory service engineers, have put two new rear ends in the vehicle with no luck.

On Saturday I picked it up after it started making noise again. It would never make the noise when I was at the dealership though. The service team had removed the rotor and looked at the vacuum plate during this visit (based on comments in other threads on Bimmerfest) and had noted that it was marked up. The interesting thing is this was on the passenger rear side and the noise could be heard on the drivers side only. I did not believe this was related but agreed to take the care back one final time before getting a replacement. The only caveat I placed on this was that if the issue happened again, I would immediately park the vehicle and they would come out to examine the issue.

It happened today as I was leaving a meeting. I immediately parked the car and called the General Manager on his cell phone. He dispatched his service manager and shop foreman out to where I had stopped. I drove slowly in the vehicle and we all heard the sound coming from the drivers rear side. The jacked up the passenger rear side. Removed the wheel. Removed the brakes, and removed the rotor. When the rotor moved slightly a small pebble fell free from the vacuum plate and hit the ground. It was about the size of 1/2 of a green pea. They reassembled the rear and had me drive the vehicle. The sound was gone.

They are notifying BMW of this issue so a service bullpen can be put together. $4000 in rear ends and 45 days without my car for a little pebble.

My hat goes off to Flow BMW in Winston Salem for not giving up. Doug Weaver and Ricky Stevens especially.

By chance does this rattle sound like you're dragging tin cans behind the rear of the car?

Originally Posted by rdollie

By chance does this rattle sound like you're dragging tin cans behind the rear of the car?

Much talk about this issue.. some relate it to sounding like a cowbell.

http://www.google.com/search?client=...UTF-8&oe=UTF-8

Yes, I was aware of that but I'd like to know if OP's symptoms that were solved were the same as the tincan/cow-bell sound.

It sounds exactly like tin cans. What it really sounds like is a couple of empty soda cans in a dryer turning slowly. What is happening is there only is a small distance the pebble can travel before it falls down again. When it falls down the "tink" sound you here is where it is hitting the vacuum plate behind the rotor. Mine is only happening on the passenger side and the noise is only heard on the drivers side.

If you're having this problem have your service advisor, or you, call Ricky Stevens at Flow BMW in Winston Salem, NC 336.788.3333. They replaced two rear ends in my m3 before finally catching it making the noise