Abstract: A compact rack and pinion steering gear having a hydraulically operated power cylinder concentric with respect to an internal cylindrical tube slidably supporting a pinion driven rack. The piston of the power cylinder is slidably mounted in the power cylinder and on the internal tube so that the teeth of the rack can pass through the plane of fluid sealing means adjacent to one end of the power unit to provide for a shortened rack length. The power cylinder is actuated by fluid pressure and is operatively connected to a rotary valve by one external line and by an internal passage in the valve housing. Protective flexible boot seals are provided at each end of the assembly which are pneumatically interconnected by an internal passage formed by existing structure in the assembly.