Method and device for testing an installed shock absorber of a motor vehicle

The method involves setting start values of a damping constant, a spring rate, and a body mass for a wheel of a motor vehicle (4). A theoretical body vibration excursion of the vehicle is determined. Position of the wheel is optically detected by detection instants. An error function formed from deviations between the theoretical body vibration excursion and observed body vibration excursion at the detection instants is minimized. The damping constant, the spring rate, and the body mass are determined from the minimized error function. A damping measure of the vibration damper is determined. An independent claim is also included for a vibration damper test system for a motor vehicle, comprising a measuring head.