Do you mean the rubber bushings that isolate the rack from the k-member? If so, the job is not tough at all. There are metal sleeves in the center of the bushings that may be stuck but a little twisting using a crescent wrench will help to ease them out. You can use a little Vaseline to get the new bushings to slide in place. The Haynes manual has the torque spec (iirc), the nuts don't have to be "cranked" down.