I was pulling off my front wheels to inspect the brakes and grease things up today. I bumped the mirror, literally nudged it and it fell off. There are 3 studs sticking out and it seems like a metal plate inside the mirror housing. The studs are rusted bad so it was just a matter of time. Any insight on how to fix this correctly? How does that black plastic come off the inside of the door frame where the mirror mounts, is it glued? Thanks.