Not a common problem, but moisture morphing to rust and seizing the hinge could potentially happen, and when forced — it breaks. When replacing it, a drop of dry teflon lube, such as that used on bike chains, is fabulous; the carrier will evaporate, leaving a super-slick teflon fix. The cover is removable because 67/6x7 bodies were sometimes fitted with 250 exposure backs (adding very considerably to an already bloated weight and size...).