Hello, my wife has had a 451 with 71 hp petrol engine BJ 2013 since the beginning of this year. Current KM-Stand: 40000 Since the day before yesterday, a rattling noise comes from the rear as if something were grinding. I then raised the car, wheelhouse shell and V-belt protection away, and look…. the middle screw of the alternator is out and vibrates on the belt. It is practically locked, is prevented from jumping out of the belt. I tried with a Fork key to screw the screw, which apparently doesn’t work, because it must be held against the rear or the nut is missing. Strangely enough, the alternator is fixed and the belt is still on it… what does this screw hold exactly? Does the engine have to go down to get the screw fixed? I have Googled a little and read several problems with breaking bolts… but the problem should probably not occur any more at my year of construction, right? Thanks and Greetings Fredy