Abstract: The valve of a liquid fuel pressure regulator comprises a two-part construction consisting of a spherically contoured element and a stem. The spherically contoured element serves to swivelly mount the valve on the movable wall which carries the valve. The spherically contoured element comprises a hole which is on a radial to the center of the element. The shank of the stem is press-fitted to this hole to dispose the stem's flat circular head toward a seat with which the valve coacts as the pressure regulator operates. The swivel mounting compensates for misalignment and out-of-squareness of the valve travel relative to the seat and enables the head to close flat against the seat. Two embodiments are disclosed. In one, the spherically contoured element is a sphere and the hole is a blind hole drilled into the sphere. In the other, the spherically contoured element is a truncated sphere and the hole is a through-hole.