Steering Gear Rack and Pinion

The ZF steering gear rack & pinion is a critical component for precise vehicle control, converting steering wheel movement into the lateral motion that turns the front wheels. This part operates via a rack-and-pinion mechanism, where the pinion gear on the steering column engages a toothed rack. In power-assisted systems, hydraulic or electric support is integrated to reduce steering effort, ensuring a smooth, responsive, and accurate driving experience. It replaces the full rack unit, including any hydraulic or manual assist elements. Manufactured in Germany, this component is built to exacting standards. The specifications include an internal thread size of M14x1.5 and a length of 215.0mm. It is also known by OE reference numbers 99634713105, 99634713103, and 99634713104. Typical fault symptoms that indicate the need for replacement include leaking power-steering fluid, torn bellows, heavy or unresponsive steering at idle, a steering wheel that does not return properly, noise when steering, or a partial loss of hydraulic power. Replacing a worn or leaking rack is crucial for maintaining accurate directional control, driver feedback, and safe vehicle operation. A new unit ensures secure fitment, proper steering geometry, fault-free assist, and long-term durability, restoring proper steering feel, self-centering, and overall handling confidence. This steering rack is specifically compatible with Left Hand Drive (LHD) Porsche Boxster 986 models from 1997 to 2004, and Porsche 911 996 models from 1997 to 2004. It is also listed as an alternative or cross-reference for part numbers 99634701111 and 99634701110.