The mechanical seal comprises a sleeve 4 in sealing engagement with a rotating shaft C, primary and secondary sealing faces urged together via springs, and a detachable gland comprising a clamp ring assembly, the clamp ring assembly comprising a platform member 9 tightened against the shaft by grub screws 7, an orificed member 5 with threaded orifices for receiving set screws 8, and a wedge member 6 located in an annular cavity between the sleeve and the shaft. Tightening the grub screws may increase radial force on the sleeve and hold it to the shaft. The seal may have radial clamps for providing axial and rotary locking. The wedge may be Grafoil (RTM). There may be a stepped interface between the platform and orificed members. The set screws may connect the orificed member to the sleeve.