We recommend replacing your 1979-84 Mustang's steering rack bushings with Prothane urethane bushings when installing a new rack and pinion on your Mustang. Urethane does not flex like rubber for long lasting ride.
Polyurethane bushings are firm enough to control movement and maintain alignment in steering rack components without the harshness or resonance associated with solid metal suspension bushings.
Lifted or lowered suspensions, increases in horsepower, plus-size wheels and tires can subject traditional rubber suspension bushings to forces beyond their limits. Control arms, strut arms, leaf springs, body mounts, motor mounts, transmission mounts, sway bars and shocks all control movement and maintain alignment but the rubber bushings they use are designed for more "middle of the road" use. Rubber also deteriorates over time, further reducing control. This contributes to premature component failure, a "spongy" ride and less than ideal performance handling. Urethane bushings can correct these conditions, and improve drivability in your Mustang or Ford Lightning.