Abstract: A device for stabilizing the two lower steering arms (1) of a tractor, with the lower steering arms (1) actuated by a hydraulically operated power lever (9). The arms are each associated with a side strut (6) with a first single-acting hydraulic cylinder (7) for stabilizing and fixing purposes. A line connection between the first single-acting hydraulic cylinders (7) and the power lever (9) can be effected by a control valve (13). In order to center the lower steering arms (1) and set the arm to a pre-determined dimension of spread, even when no implement is attached, the line (14) which leads to the second single-acting hydraulic cylinder (10) of the power lever (9) contains a pressure-controlled first return valve. A bypass line (21) with a second return valve (22) is provided to lock in the direction opposite to that of the first return valve.