I believe where people get into trouble with the stock mirrors is that the holes on the inner panel aren't transferred before drilling from the outside. A mirror image of the mirror mounting holes are on the right for the passenger side mirror. When adding the right mirror, I transfer both of the holes from the inside using a spring loaded center punch. This leaves a small dimple outside that you can use to locate your first hole. I mount the mirror with the first drilled hole than line up the hole in the mirror base with the second dimple in the cowl as close as possible than transfer the hole in the mirror base. Remove the mirror and drill the second hole. This way the mirrors are mounted aligned with the pre-punched holes in the inner panel as they were meant to be.
If you can’t access the nuts then the holes are simply in the wrong place. This is the driver side and the passenger side is as mentioned, a mirror image.
http://www.pbase.com/dennygraham/image/133002026/large Denny Graham
Sandwich, IL
