Bicycle Tutor

My shimano 105 front brake won't release after engaging. The problem seems to be the arm spring connects through a plastic sleeve. The housing is broken: on the functioning brake, the spring/sleeve/brake move as a group. On the broken brake, when you pull the brake lever, the spring just slides through the sleeve and gets stuck. Does anyone know how or even if I can replace the spring/housing? Or is there a work around?

Can you post a picture? I'm having a hard time understanding what parts you're referring to. Is it possible that it is the cable that comes down from the brake lever that is fraying?