I don't really know how to describe this problem that I am experiencing once in a awhile. So ok I start up my car warm it up abit and then step on the brake pedals and then shift the gear into D and then release the handbrake. So once I release the handbrake there would be a huge clunking or thumping noise following with a bit of force coming from the back of my car like someone hiting my car from behind slightly and then my back suspension and back end of my car would itself slightly. This have happened to me for like 5 or 6times already and I am kind of nervous cuz I have not experienced this with any car I have driven before. So have you guys experienced this problem with your Mz3 and does anyone know what seems to be the problem? Iam not sure if this is caused by the handbrake, braking system or any other parts of the car . I hope I haven't broken or screwed up my car majorly. thanks for any replys hope you guys understood what I said.