The invention relates to a shock absorber with a housing, an inner pipe arranged in the housing, a piston rod, a piston which is arranged at that end of the piston rod, and which piston divides the interior of the inner pipe into a lower chamber and an upper chamber, a first valve arrangement which is arranged on the piston, and a third valve arrangement which is arranged at the lower end of the inner pipe and by means of which the working medium which is held in the interior of the housing, serving as a tank, can flow out of the interior of the housing, only into the lower chamber when the piston moves in the inner pipe. The shock absorber is distinguished by the fact that a hydraulic pump drive is arranged between a first connection element of the lower chamber of the inner pipe and a second connection element at the upper chamber of the inner pipe.
