A process and device are disclosed for measuring multiple disk brake wear, in particular of shafts with planetary gears, by inserting a screw (16) containing a measurement device (13) into a predetermined bore (17) in the wheel hub. The measurement device has a spindle (14) which is concentrically guided within the setting screw and which is moved up to the multiple disk-supporting washer (10), after the brake is actuated and before the wheel hub is further rotated, and this distance is determined as a first measurement value. The brake is then loosened and the spindle (14) is moved until it comes once again to bear on the supporting washer (10), and this distance is determined as a second measurement value. The difference between the two measurement values gives the piston hub, i.e. the wear of the friction linings (8).