Abstract: A modular, bolt-in, rack and pinion assembly for replacing an existing steering gear box in a motor vehicle. A rack tube, including a pair of elongated slots in its sidewall, houses the rack. The rack tube is mounted to existing holes in the frame of the motor vehicle by means of a plurality of brackets. The rack has a tooth portion and a shaft portion. A pair of studs projects transversely from the shaft portion of the rack, each stud passing through a receptive slot. The studs are mounted to an elongated center link. The vehicle's factory tie rod assemblies are bolted to either end of the center link. A pinion housing is secured over a proximate end of the rack tube, maintaining a pinion gear in threaded engagement with the rack. In a manual embodiment of the invention, an outer end of the pinion is connected directly to the steering wheel shaft. In a powered embodiment, a servo having its own pinion gear is bolted to the pinion housing.