I just got new avid disc brakes for my bike, front and rear. i have them installed but i am having a really hard time getting them to work right. Right now when i apply the brakes i slide to a stop and dont come to a complete stop right away. as of now my old no name rim brakes work waaayyyy better than the disc brakes. I followed every step of the directions and they still dont work right. any tips would be helpful.