Originally Posted by guy99
My driver side rear view mirror can not be locked down because the set screw is frozen. I assume that it is frozen because the set screw is steel and the mirror fixture is aluminum.
Penetrating oil hasn't helped so far.
Any more ideas?
Apply some heat to the area. The aluminum will expand and contract at a different speed fromt the steel, and after heating it up, try loosening it before it cools off again. Just be careful, as aluminum melts at a much lower temp than steel.