I have a couple of problems with my brakes on my Specialized Hardrock with cantilever brakes.

1) One of the brake arms doesn't move when I squeeze the lever. Thus, only one brake pad engages the rim. The arm is a bit "stiff", but I can move it back and forth using my hand.

2) When I turn left, the brake pad is hitting the rim. When I go straight, there is no friction.

Thoughts?