Door mirror brackets on 70 c-10

[ktztrk]

I have mirrors that are said to be for 67-69 chevy trucks that have a triangular mounting flange that matches the flange on my truck doors. There are three holes at the points of the triangle and a center hole. On my truck, there is a bracket on each door that matches the mirrors.
Is there a re-enforcing piece behind the bracket and/or do I have to remove the bracket to install the mirrors? I have taken a pic of the bracket, but will have to do research to learn how to upload pics.

I have tried to upload from my pc to the board, a jpeg file that shows the brackets. It is shown as an attachment in the additional options section as olshotgun2.jpg.
Any help is appreciated.

[Brad]

Yes, there is a reinforcing bracket inside the door of the same shape. I think it's spot welded on, but after 35 years they tend to rust and fall off when the bolts are unscrewed.

[ktztrk]

Thanks for the info. I shall use my peeper device to check the inside of the door.

If all is OK, do I just remove the screws, or do I remove the outside plate before
I install the grommet and bracket on the door or amI supposed to install it over the outside plate. Appears to me that the outside bracket should be removed.

Will respond when I check the inside of the door. Hope for the best.

[ChevLoRay]

I think that by removing the screws on the outside of the bracket, you'll be able to hear the inner piece as it falls to the bottom of the door.

[yank]

looks like that truck has had every mirror possible on it at one point in it's life time.

[ktztrk]

Status of mirror installation:
Here is where I stand on the mirror on my 70 C-10. Pics attached.

I must say that no miracle happened, I just submitted a pic
of the brackets before the paint job.
And yes, the truck has seen a few mirrors, but
I think these should work best.

So, I was able to remove the six screws at
the corners of the bracket, but not the center screw.
The screw on the driver side snapped off and
the shotgun side is loose, but will not come out.
It spins some kind of flange behind the bracket.

I do not understand the purpose of the center screw.
Could someone explain?

I have temporarily replaced the original screws with
stainless screw that came with the mirrors.
I was able to that by not removing all of the originals at once.
Since the seal for the new mirrors are flat,
I must remove the bracket (flange) or what ever that is on
the outside of the door.
The stainless screws are long enough for me to start them
one at a time through both the mirror bracket and the seal.

I may be able to complete the job without removing the door panel.
Am I missing anything?
Thanks.

[SLIMJIM]

Those mirrors came on '70 models as well, not just 67-69. I have them on my '70 Blazer 2wd, and they are factory. Good luck.

SLIMJIM

[Tx Firefighter]

Those are old mirrors bases that someone has hacksawed the arms off of. Those are not special plates or anything like that.

Here's the one on my truck after I brazed the arm back on.

[ktztrk]

Well, the mirrors on my 70 have gone full circle.
Thanks everyone for responding, I was able to glean enough information to be
able to get the old brackets off and the new brackets and mirrors back on without dropping the inside plate or taking the door panels off.
Was able to perform job in about an hour for both doors.
Just a few more things to do and I shall upload pics.
Thanks again. Completed pics attached.