Hi, I have an 05 MCS. I got in an accident a couple weeks ago and am now back on the road. There is a rattling noise in the rear when I hit a bump. once I hit the bump it starts and sounds like it goes around as the wheels do. Once I come to a stop it stops and doesnt start until I hit another bump. I was thinking it could've been a wrench that I may have left on top of the battery. I also thought it could've been maybe an exhaust hanger and maybe the muffler was rubbing on something. I have no clue what it is at this point. Anyone have any suggestions? I was hit in the front so I don't think it could be something that was hit in the back.

 

When you hit the bump the rattle sounds rotational? I'd probably get your MINI up on some stands and rotate the wheels and check components out to see if anything appears loose or damaged.