The outer door mirror(s) is attached from the
outside, not the inside. Look at the lower edge of the mirror base, and you'll see a small, allen-head set screw. Take the set screw out, and the mirror will lift off. The mirror base is held to the door with two phillips head machine screws. They may be loose, or the set-screw for the mirror could be loose....either one will make it flop around on the door. Be careful tightening the set-screw in the mirror, tho, as the screw is easily snapped off if tightened way too tight.
If you have the AIM for your '73, 90% of it will also pertain to the '70, as far as stuff like this.
______________
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"