After doing much research and noticing that even after the plastic ring that attaches to ball joint in the back popped off as long it was a cool cold day it worked fine until it got warm or hot out! I popped that plastic ring back in twice and it worked again even in warm weather but it didn’t last long!
people out West like AZ. Seem to have this problem a lot. I since then paid 205.00 for a new rear view mirror but no guarantee how long before it happens again in extremely hot weather we had the hottest summer on record this year.
However I found on YouTube a lady who found a way to keep that ring in place with a tie strap going under the mirror where the little lever is to switch day and night visibility where there is a slot where to slip the tie strap through and tighten that ring where it will stay in place.
I hope this gives light to this problem we obviously all have.
The YouTube video is called
“Hack for German cars rear view mirror drooping and loose”.

 

Yes, not sure if that is the same video, but I did solve it with a tie wrap. I was going to get the official BMW tie wrap at the dealer but it was $150.

 

Thanks for this. I used this method with the mirror off. That allowed me to apply to proper pressure to the zip tie so I didn't need to apply any epoxy. A lot more movable in the summer here in Las Vegas, but it doesn't flop around. In cooler temps of Fall and Winter here, it absolutely stays put. Going on 2 years without any issues. Car is garaged so I think it will last a while.