A divided driver device (5) for a mechanical face seal for non-rotatable assembly on a rotary component and for the transmission of a torque to a seal ring (2) held in non-rotatable manner on the driver device. The driver device (5) is divided in at least a single radial plane so as to form sections in the form of segments of a circle that are adapted to be clamped together to form a ring shape and furthermore, it is axially sub-divided into a divided retaining ring (14) for retaining the seal ring (2) and a divided mounting ring (16) for non-rotatable mounting to the rotary component. The rings (14, 16) are coupled together for rotation in common, as indicted by (24). The retaining ring (14) comprises mutually sealed sections (14.sub.1, 14.sub.2) in the form of segments of a circle which are adapted to be placed together to form a ring shape having an inner radial dimension that is greater than the nominal outer radial dimension of the rotary component concerned (6), and said sections comprise peripherally aligned end faces (15.sub.1, 15.sub.2) which are preferably in metal-to-metal contact with one another and have a surface finish for mutually sealing them.