91-94 Caprice Upgrade Mirror Install
Top window spear is stock 91-94 Caprice and the bottom is 95-96 Caprice, Buick and Impala
I cut out a paper template to match the pattern of the late model spears then cut out my stock ones to match. If you print this picture to scale then you can use this as your pattern.
What it looks like before the holes in the body are drilled
Remove the door panel and unclip the upper window trim so you don't drill thru it. Match drill the two holes for the mirror alignment pins 11/64. The upper one is slightly slotted. Then match drill the three bolt/stud holes for the mirror mounts. I used a 3/4 hole saw w/ 1/4 inch pilot drill that was extra long. After sawing out the front hole I discovered that there is not any reinforcement behind it so when I drilled the passenger side I only drilled the 1/4 inch hole. Also cannot use the stud that's on the mirror so I removed it. I don't know about later years if that is present. Once you have the two 3/4 inch holes drilled then slide the hole saw thru the hole and drill the two 1/4 inch holes in the reinforcement then the inner door skin. I used a 1 5/16 hole saw to drill the opening for the wiring to pass thru but think a 1 inch would work just fine.
On the inside of the door using the 1/4 inch holes that you drilled thru the door as guides drill the 3/4 inch holes only thru the skin. Once thru you will see the reinforcement and that's where the mirror bolts/studs will bolt to. Unplug the stock mirror and remove the two nuts that hold the mirror and set it aside. Hold the new mirror in the new place and loosely start the two rear bolts then using a ~1/2 long bolt you can reach inside the door up to the front hole in the door to the mirror and tighten the bolt. Removing the door speaker will give you to reach thru there and install that bolt. Tighten the other two bolts then make very sure the mirror wire goes behind the window track and plug it into the door harness. If you want to temporary plug the mirror switch back in you can test to make sure everything works.
Snap the trim back in place and reinstall the door panel, you are done.
Now all I need to do is fill in the stock holes. I cut a couple filler panels to weld in and will shave the rear door handles at the same time.