I would disconnect the cable and remove the brake and give it a good servicing, most likely it needs to be lubed and adjusted ( let alone cleaned & polished LOL ) before putting it back on the frame. As I am reading this morning I am doing just that to a set of brakes from a Lotus that sat outside while sitting at my computer/work desk. The brakes were stiff to move, a little elbow grease goes a long way.

Glenn