my mirror does the same thing and yes I said mirror only has drivers side not sure why the po removed the passenger side but oh well ive looked and I cant figure a way out to tighten them may just need to get new mirrors
There are many obstacles that life throws at you, but you gotta make like a jeep and crawl over them and continue on.
Ok so the only solution to this I found on accident. Behind the glass is 2 bolts that need tightened down as well. Yes I said behind the glass. My pass side was broken and I was curious. Well it worked. There should be 2 screws on the bottom of the mirror if I remember right that will help a little but those bolts behind the glass seems to tighten the swivel of it or something. Been too long ago and way too many beers.
Help restore faith in humanity, do something nice! KCCO