Fitting electric?big mirrors

[rikg24]

I have recently bought some big mirrors but they have 3 screws fixing them to the doors not the 2 on none electric mirrors what is the best method of fixing for the third hole if that makes any sense?

[R0B]

I used an Allen bolt and nylock nut.
Makes nicking them more difficult as well.

[rikg24]

I used an Allen bolt and nylock nut.

did you just fit the mirrors with the 2screws and then drill a new hole for the third / new
one

[Plasticman]

yes, and i usually weld a plate in the back to save the 3rd screw crushing the door in a bit, they dont all do this and you dont need to weld as a gasket will do as long as its not too deformable
mm

[Aidan]

originally they use a rivnut, and if you fit a nylock on the back of it it helps stop the mirrors being stolen but you have to be careful with the rivnut installation easy to deform the panel if you are heavy handed and alloy ones potential dissimilar metal corrosion