My rear view mirror came off today while in work. Probably due to age and scorching Texas heat. What do I need to do to glue it back on? and what kind of glue should I buy to do it with?
Go to Napa, Autozone, Pepboys or similar - they all stock the specific glue that you need to reattach the mirror.
As with most jobs that involve sticking dissimilar materials together, cleanliness is the key - make sure that you get all the old glue off both the windshield (fairly easy) and the metal button (not that easy). Follow the instructions on the pack to the letter. I had to reglue the mirror on my wife's Cherokee a few months back, it's a really easy job, just take your time with the prep and give the glue enough time to harden before you put any load on the metal button.