My passenger side one is fine but the drivers side swivels back at highway speeds.

How is the best way to fix this?

A friend said he had his done under a recall years ago.
They replaced them with the chrome ones.

 

There are 4 bolts that hold the mirror clamp onto the mounting bracket. The clamp holds the round shaft on the mirror to the mounting bracket. Unfortunately, the bracket is aluminum and the threads strip, causing the mirror to fold back at speed. Take the mirror off, then drill and helicoil the aluminum mounting bracket for 1/4"-20 UNC bolts.

 

Or you can do what I did, put nailpolish inside the threads and tighten all four bolts one turn at a time. Now my mirror is so tight I almost cannot adjust it.