An actuation device for machine elements having wear-induced play, especially for brakes in rail vehicles, has an actuating piston-cylinder unit which generates actuation force and has a piston rod. The piston rod cooperates with a readjusting device which compensates for play caused by wear and which supplies the actuation force to the machine element to be actuated such that wear play is compensated. The readjusting device comprises a hydraulic piston-cylinder unit which carries out the wear play readjustment through the extension of an adjusting piston. To actuate the adjusting piston, a sensor element detects the wear-induced play and, when a threshold amount of wear-induced play is reached, opens a valve which admits a hydraulic medium to the readjusting piston-cylinder unit by utilizing the operating pressure of the actuating piston-cylinder.