A steering rack piston assembly (10) employed in a power steering rack and piston assembly. The assembly includes a shaft (bar) (11) upon which there is mounted a piston (12). The shaft (11) has a longitudinal axis (13), that is also the longitudinal axis of the piston (12). The piston (12) has an outer groove (15) that receives a seal (16) that slidably engages in a cylindrical surface of an outer housing that is not illustrated. The piston (12) and shaft (11) move along the axis (13) relative to the outer housing as a result of pressure within the fluid located on opposite sides of the piston (12).