Abstract: A motor vehicle steering column having thereon an electric power assist apparatus including a tubular mast jacket, a structural housing, a socket in an end wall of the housing consisting of an annular seat and a cylindrical guide wall, and an annular plate attached to the mast jacket. The plate plugs into the socket and bears flush against the seat with the edge of the plate fitted in the cylindrical guide wall of the socket so that the centerlines of the mast jacket and the housing are precisely aligned. A C-shaped retainer in an annular groove in the cylindrical guide wall overlaps the plate to prevent dislodgment of the mast jacket from the housing. The retainer has a beveled shoulder which bears on an edge of the groove and converts circumferential expansion of the retainer into longitudinal thrust on the plate to eliminate lash between the plate and the housing.