The GMC control arm bushing is another polymer component that prevents the metal to metal contact between the control arm and chassis on your truck. Because it is a type of cushion and stress is placed on it, replacement may be required periodically. The importance of the control arm bushing is more than just cushioning the contact area of two metal pieces, the control arm and the frame of the vehicle, but also the alignment of the wheels on your GMC truck. When the polymer portion of the control arm bushing becomes wider from being worn, the steering wheel begins to change direction ever so slightly. The resulting action is the premature wearing of the vehicles tires. The GMC control arm bushing is the suspension component that makes a contribution to limiting the lateral movement of the wheel. When this contact point begins to wear by splitting or cracking, a vibration usually occurs. As the wear on the control arm bushing increases so does the vibration in the body of the GMC truck. Replacing this bushing is easy to accomplish if you have a press. The load has to be removed from this auto part by lifting the wheels off of the ground. Once you gain access to the area of the front where the spindle is located then the control arm and its bushing can be seen. By unbolting the control arm and removing it, the old bushing can be pressed or hammered out and the hole it occupies can be inspected. All of the old bushing must be removed before the new one is put into place. Once this is completed the new control arm bushing can be put into place and the suspension component can be reattached to the GMC truck.