A hydraulic power assist rack and pinion steering system (12) for a vehicle includes a housing (14) in which a rack (10) is movable along an axis (16) to effect turning movement of steerable wheels of the vehicle. The rack (10) comprises a first rack part (50) having an elongate body portion (56) and an end portion formed as a first piston portion (58), and a second rack (80) part having an elongate body portion (86) and an end portion formed as a second piston portion (88). The first piston portion (58) of the first rack part (50) is joined to the second piston portion (88) of the second rack part (80) to form a piston (22). The body portion (56) of the first rack part (50) extends axially away from the piston (22) in a first direction (110). The body portion (86) of the second rack part (80) extends axially away from the piston (22) in a second direction (112) opposite the first direction (110).