Not sure which screw in particular you are talking about (pics?) but maybe the mirror has been replaced before and they did it up too tight; lots of WD40 and gently tapping the screw with a hammer tends to work for me when things don't budge, if the screw head gets worn things get even more annoying/impossible so best not to go too rough if it can be avoided.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.