A system for mounting an annular component on a shaft, comprising (a) a hydraulic nut having an annular coaxial cavity and a ring-like piston, displaceable within the cavity; (b) a displacement sensor for providing a displacement signal indicating the axial displacement of the piston within the cavity; (c) a wireless displacement transmitter for transmitting the displacement signal; (d) a pressure sensor for providing a pressure signal indicating a pressure within the cavity; (e) a wireless pressure transmitter for transmitting the pressure signal; (f) a pump arranged to pump fluid into the cavity; and (g) a remote control device having a communications device arranged to receive transmitted pressure and displacement signals, wherein the remote control device is arranged to output control information for controlling the pump.