Help with an xbox 360 controller malfunction

I have 2 Xbox 360 controllers with the left analog stick's dead zone sticking. That is to say that if the joystick is nugged slightly and put down, it constantly registers a small movement in the direction it was nugged until you re-center it. I've tried taking it apart and cleaning it, but it seems the spring inside the analog stick unit is worn out. I've searched google, and the only broken controller hits I got was for the stick breaking off completely from the analog unit. Any insight as to how i could fix this problem, or am I better off trying to make 1 good controller out of 2 bad ones by taking the right analog unit off one and soldering it on the left analog port on the other?