Auto body repair & detailing: passenger mirror, passenger mirror, glass assembly

Question
I had to replace my passenger door mirror on my 1994 F150. I bought the mirror from a salvage yard instead of buying a new one so it would match a little better as far as fading, etc. The mirror fit perfect except there is just enough slack between the mirror and the mount it sets on to cause vibration and some rattling. It was the only one they had. Is there anything I can put between the two pieces to stop this?
I would appreciate any advice at your convenience.
Thank you in advance.

Answer
Sounds like there is something wrong with the mirror. I wouldn't have so readily accepted a faulty mirror, because you probably need toremove the glass assembly from the housing to work on it. It's damn difficult to remove a glass assembly without breaking it. Buy used, you get used, my friend. Break away mirrors can be a real pain in the ass to work on, and the spring in them is under a lot of pressure. You might get it apart, and never get it back together. I don't know how to repair your particular mirror, we always throw away mirrors when they start acting up. Everything is plastic, so repairing them is out of the question, they won't hold up worth a crap. Sorry I don't have better news. Bill