I used this technique, link below. Great, great resource. Try it, you'll love it!

http://www.corvettefaq.com/c3/chrome_mirror.pdf

I did have two problems; First, although I soaked my mirror for 24 hours in gasoline, as instructed, the glass needed prying to get off, which was tricky without damaging the glass, Second, it was very difficult to squeeze my shim in under the head of the rivet. I had to push down very hard on the outside of the tension bar with a screwdriver to create a little gap, and then my shim sort of crumpled up as I tried to slide it in. I had to use a very thin washer for a shim because it was so tight. I did get enough of it in and certainly the JB Weld will keep it all in place.

I added one little step, once my shim was in, I used a center punch on both rivets and whacked them a couple of times just to help reset them after 41 years.

The mirror now has a tremendous amount of tension, while still being easily adjustable. Clearly now when I goose the throttle, I'll be able to see the cars behind me getting smaller and smaller, instead of just seeing the side of the door!

 

Good info.
Mine flops around. peening the outside helped, but, not enough.

 

I clean up the stud with brake parts cleaner, while twisting the mirror around then add some Red Locktite. Works pretty well for a few months, then needs refreshment treatment.

 

I put on late shark mirrors, that way when people walk by the car the mirrors stay adjusted....

them chrome jobs are junk and very surprised they lasted long as they did on the sharks....all other cars in the lineup had good mirrors long before the vette....must have been a large stock of them on hand, or a contract of some sort they had to honor....

 

Doesn't the fact that they've lasted so long sort of mean they weren't junk?