1990 truck, I removed the mirror to get the inside of the windshield cleaner. When I installed the mirror I didn't even get a chance to tighten the screw and "tink" it came off in my hand.
No problem, off to NAPA. I buy the super dooper mirror fixer kit, follow the instructions and put it back on, I've done it before. It says to wait 15 minutes but I waited a few hours before putting the mirror on the button; "tink" comes off. Do it again, this time waiting over night.
"Tink"
Rats.
Another kit, this time I use acetone to clean the windshield instead of the stuff in the kit.
"TINK
Now I'm getting cranky.
Another kit, acetone, overnight:
"TINK"
AAAaaaaarrrrrgggggghhhhhhhhhhhh !!!!!!!
How do you drill a hole in glass?
You have to clean the glass really, really well, and even then in my experience the glue you buy at the auto parts store doesn't last more than a year or so. However, it shouldn't fail as fast as you're seeing. I wonder if the glue kits have been sitting on the shelf at the store too long.
I too had this problem. Clean it well and glue it back on with the kit and wait days before putting the mirror back on. Worked for me on our Lumina.
RossD
SuperDork
7/25/11 8:28 a.m.
Did you clean the tab, too? Rubber gloves will help keep your greasy paws off of the mating surfaces. 
I had the same problem with the mirrror on my 318ti when I bought it... it's been hanging there 5 years now without even a hint of falling off
go retro and buy an old-school mirror that screws into the sheetmetal at the top of the windshield?
RossD wrote:
Did you clean the tab, too? Rubber gloves will help keep your greasy paws off of the mating surfaces.
This. IT's amazing how just a little bit of oil from your fingers will prevent adhesion. By any chance are you a smoker? Then, even though you used acetone, first scrub the glass clean with windex, allow it to throughly dry after cleaning, then wipe and clean with acetone, and try again. Follow the glueing directions to a T. And as another poster pointed out, yeah, let it dry all day. Also, when you place the button on the glass, tape it tightly against the window. It's easier with a helper.
If all that doesn't work, time for some 24 hour epoxy.
I agree with other posters who suggest cleaning the part that attaches to the window, as you've obviously tried cleaning the window. Is the mounting surface of the mirror foot absolutely flat? If there's old glue or any surface irregularities, that will prevent a good bond with the glass.
C. R. Lawrence. They are providers for professional glaziers. They have the stuff that actually works.
usually the "button" is not a very tough metal.. I wonder if hitting it with some sandpaper to roughen it up some would help?
My latest attempt is Crazy Glue. This weekend it was terribly hot, I hope that has some play here. Right now it's 70 and raining, better I hope.
Dan
we put the tab on the wire spinning wheel ,, use alcohol and we tape tab to window . Do not attempt in hot sun . leave for a 6 pak of time
