An apparatus, according to various aspects of the present invention, adjusts fluid pressure. The apparatus includes a body, a seal seat, a sphere, and an adjustment rod. The body includes an axis and an adjustment passage. The adjustment passage is positioned angularly to the axis. The seal seat includes an adjustment end portion. The seal seat is disposed in the body and moves along the axis. The sphere is disposed in the body and moves angularly to the axis. The sphere contacts the adjustment end portion of the seal seat. The adjustment rod includes a first end portion and a second end portion. The adjustment rod is movably disposed in the adjustment passage. The first end portion of the adjustment rod contacts the sphere. The sphere in cooperation with the first end portion of the adjustment rod and the adjustment end portion of the seal seat translates displacement of the adjustment rod into axial displacement of the seal seat. The adjustment end portion of the seal seat includes a groove having a ramp. The sphere moves in the groove.