An assembly for positioning a retaining ring includes a mandrel having an outer diameter smaller than an outer diameter of a rotor. The assembly also includes a seal assembly for sealing a circumferential retaining ring around the mandrel or the rotor, the seal assembly comprising a pair of seal plates situated around opposing ends of the retaining ring. Further, the assembly includes a hydraulic expansion device for providing a fluid pressure for hydraulically expanding the retaining ring until an inner diameter of the retaining ring is greater than the outer diameter of the rotor. Furthermore, the assembly includes a displacement device for providing axial movement of the seal assembly and the retaining ring.