A variable effort automotive power steering gear including an input or stub shaft, an output shaft or pinion head, a torsion bar between the stub shaft and pinion head defining an open-center position of one relative to the other, and detent reaction apparatus between the stub shaft and pinion head. The detent reaction apparatus includes a radial socket in a cylindrical wall of the pinion head, a detent groove in a stem of the stub shaft in the cylindrical wall, an insert rotatably supported in the radial socket with an eccentric bore offset from the centerline of the radial socket, and a detent element slidably supported in the eccentric bore in the insert and having a spherical end adapted to seat in the detent groove. The spherical end of the detent element is centered in the detent groove by rotating the insert until the detent element is at an innermost radial position. The adjusted position of the insert is captured by an in-situ injection molded plastic retainer on the pinion head in a wide annular groove in an outside diameter of the cylindrical wall which engages an exposed cavity on the insert. The retainer has a pair of annular end walls facing in spaced relationship a pair of annular shoulders on the pinion head which form the sides of the wide annular groove. The annular shoulders and annular end walls cooperate in defining a pair of seal ring grooves on the pinion head.