It is an adjustment shim for your rear trailing arms. The shims space the pivot point of the arm away from the frame to achieve rear toe adjustment. DO NOT DRIVE YOUR CAR if this has fallen out as it means that the bolt is now either broken or loose and potentially VERY dangerous. Any dealer can sell you the replacement bolts and shims. Cheers, Nick To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/