The invention provides a mirror assembly adapted to be mounted on a mirror support. The mirror assembly includes a convex mirror glass and a rear plate having an exterior surface, an interior surface and an aperture, and a seal between the mirror glass and the rear plate. The mirror assembly also includes a pin including a head, a ribbed portion, and having a longitudinal axis. The mirror assembly further includes a ball joint comprising an inner ball portion and an outer ball portion. The inner ball portion includes a first bore extending therethrough and an engagement surface for contacting the interior surface of the rear plate. The first bore is aligned with said the aperture for allowing passage of the pin. The outer ball portion includes a concave engagement surface for contacting the exterior surface of the rear plate and a second bore extending axially through the outer ball portion. The second bore is aligned with the first bore for allowing passage of the pin.