The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Outside Mirror Installation.

Hey guys, I'm going to purchase a set of stainless outside mirrors to put on the doors of my 66' GMC Burb. Currently have a crappy, cheap set on them. How do I find out the exact dimensions to place the base of the mirrors? I am worried about them looking correctly. Any advice would be greatly appreciatedd

All light-duty turck driver side doors have a weld plate with three threaded holes, to receive the sport-style mirror. Sometimes they are welded up or filled with body filler, but they are still visible from the inside of the door shell with the innder door panel removed. Additionally, the passenger side door shells have a reinforcing plate in the mirror area, with three holes drilled in it, that is also visible from the inside of the door shell with the inner door panel removed. These three holes are not threaded, nor do they have a weld nut, but they are in the proper location, as determined by the factory reinforcing plate on the inside of the door skin.

If you locate them, in a location other than where these holes are, you run the risk of hitting half the hole and wallowing out the outer sheetmetal skin, when the bit tries to run into the factory holes.

Thanks Tony, I've not had a chance to remove the inside door panel yet but I was hoping there would have been some type of reinforcement bracket. If this is the case then I should be able to maybe drill the holes out from the inside. Thanks again.

My 66 gmc had the reinforcing plate on the passenger but no nuts so we drilled them out and bolted it into place. Kieth

we used the new mirror as the pattern to check the plate with.

Tony
How does one mark on the (exterior) the location to drill the holes so as to make sure alignment with passenger side backing plate. I have found the passenger side backing plate and the 3 hole pattern but have not figured out how to transpose the location to the exterior to mark for drilling.
If you have a method.
HB

I measured to find one hole and drilled it. Then I used the mirror base as a template to drill the other two.

Will a right angle drill and a short bit work from the inside, working on my 65 jimmy and would like to use the stock appearing brackets with the larger SS heads, thanks.

Right-angle drill & short bit is one way, as mentioned by Squareparts2. You can also use a spring-punch from the inside. It will put a very small divot in the metal, from the inside, that can be picked up on the outside. After finding the first hole, I use a Unibit from the outside to find the first hole. Carefully drilling out the hole with a Unibit, will find the center of the first hole, relative to the backing plate. The rubber mounting pad, serves as a good template for the other two holes.

Backing up these bolts can be a bit daunting, so using a Riv-nut is also a good solution, in lieu of a sheet metal screw or bolt & nut. Riv-nuts and the setting tool are available at most well-stocked hardware stores. I don't recommend using sheet metal screws, since they are prone to pull out.

The bottom hole on the reinforcement plate is threaded. Perhaps running a bolt with a sharpened tip through the hole into the fender enough to dimple it would mark the spot to drill the finder. This would insure that the mirror bolt will thread up correctly with the plate.

Use a spring punch through the upper hole to dimple the fender. Then mount the mirror with the "threaded" bolt to fine-tune the location of the upper hole. It may not be exactly on the dimple.

Just a idea. I haven't tried it.

My truck's po drilled from the outside without using the reinforcing plate to mark the location. This resulted in an extra upper hole in the reinforcing plate and buggered threads on the lower hole.

thanks for the ideas. Gives me a new strategy.

We used the spring punch method finding 2 with the punch then the third with the mirror. worked great. Kieth

Off to get a spring punch.

Went looking for a spring punch. No luck yet, but I have not the good spots yet.
But as I probed the inside of the door panel, finding the reinforced hole area, How do I get the punch and my hands in there to center the punch and make the mark. I suspect there is an easy answer that will lead me to hit myself for asking the question.

HB