In the past using some form of lubricant to ease the movement can if you use too much give the opposite effect and you get a mirror that keeps drooping, sounds familiar at my age.
I've opted to get another mirror, my l/h is the problem just in case either it breaks or I go for the silicone treatment and it drives me nuts having to keep moving it back where I want it, after awhile the silicone will dry out a bit and if lucky it will hold position.
D.
