J&M's all new Upper Control arm bushings found in the Mustang automobiles can have a significant impact on the vehicle's handling. When the car leans (i.e., rolls) in a turn, one side of the chassis moves upward relative to the rear axle, the other side moves downward, and the upper control arms must twist to allow for the axle to articulate. This causes the upper control arm bushings to bind. If this bind becomes excessive, it will raise the rear wheel rate and produce sudden, uncontrolled, undesirable changes in handling (e.g., snap oversteer).
Ford minimizes this suspension bind by using compliant rubber bushings in both the upper control arm housing bushings. These relatively "soft" bushings help accommodate the necessary motion of the control arms during body roll; however, the rubber bushings do not provide much in the way of forward and aft support, which causes wheel hop during hard acceleration and braking.
It has become common practice to replace the stock rubber upper control arm bushings with solid or two piece polyurethane bushings to resolve the shortcomings of the soft factory rubber bushings. Hard polyurethane bushings eliminate wheel hop, reduce axle deflection, and improve rear straight line grip. However, the downside of common aftermarket bushings such as delrin, steel, stiffer rubber, solid or two piece polyurethane bushings is that they prevent the necessary movement of the control arms during body roll, which in turn produces significant binding in the suspension when the vehicle is cornering. The polyurethane bushings also place unnecessary high stresses upper control arm body mounts, which are the attachment points for the upper control arms to the chassis. Standard aftermarket control arms do not allow for rotation of the control arm during cornering because of the stiffness of the bushings. J&M Spherical Bushings for the upper control arms eliminates the disadvantages and has significant advantages beyond other available products that do not incorporate all these design features
79-04 Mustang Upper Rear Control Arm Aluminum Spherical Bushing J&M Products, Features and Benefits:
- 52100 heat treated steel/hard chrome plated ball
- Bearing race is heat treated 4340 chrome moly
- Bearing liner is attached with a thin sintered bronze wire net impregnated with PTFE powder, same as modern ball joints.
- Reduced torque arm deflection over factory rubber bushings
- Increase traction, reduces axle hop
- Reduces snap oversteer
- Quicker vehicle reaction times, less suspension "take up"
- Creates more predictable straight line handling and when cornering
- Lifetime warranty
- New 10.9 hardware included
