Mine does as well. The top case floats on top of 4 rubber bushings so it is intended to have some ‘movement’ or ‘suspension’. 4 M8-35mm (T45 Torx) are used to screw up from underneath the case into two base plates/nuts that you will find underneath the carpet in the case. (That with four plugs that open to access the 4 bolts that connect the whole assembly to the rack.. no need to touch those, but double check every once in a while to make sure they at right)
Ahh yes, make sure to ream the receiving nut with your M8 thread repair tool. Whatever BMW uses to ‘fix’ these bolts in place leaves its residue and you won’t get the replacement bolt in without a good reaming/cleaning first. After that. Smooth sailing
Back to the 4x M8-35mm. They are black in colour and appear to be fixed into position with something like red Locktite. Problem is, they are fixed loose enough to allow the case to rock back/forth some 1-2cm, which irritates the heck out of my Nordic mentality. It no doubt creates more vibration to the case than necessary. Better would be to tighten them just a little bit so that the thick rubber bushing makes ‘contact’ and everything is firm (without losing the desired suspension).
Problem is, the four bolts are really fixed tight and there is no rational way to apply heat to them without managing the case. I had one bolt snap in trying to tighten it, forcing me to drill it out and apply an extractor. With that I can replace it with a much nicer stainless/black bolt that will be easier to remove, case is now tight(er). Will attack the other three and replace those (with BLUE loctite this time) to get it nice and firm.
I think the production lines just don’t set the tightness where it should be, or the rubber bushing shrinks, causing the looseness.
