Movement of an elevator cab drive sheave is controlled by a disc brake/load weighing assembly which is operably connected to the output shaft and sheave of the elevator drive machine. The disc brake assembly acts as the operating brake for normal operation of the elevator, and can also serve as an upward or downward safety brake. The brake assembly can be retrofitted onto an existing elevator system, and its operation is not affected by any gear degradation in the machine drive gears. The brake when it is set acts to impart movement to a torque arm which is operably connected to a load cell mounted on the machine bedplate. The load imparted to the load cell is proportional to the weight of the cab and its occupants. The load cell is connected to the elevator controller and imparts a load signal to the controller each time the cab stops.