Abstract: A tractor-drawn farm implement is carried at its front end on a tractor drawbar and at its rear end by trailing wheel means, and linkage of the so-called four-bar type is operative to selectively raise and lower the implement. The body of the implement serves as one member of the linkage and front and rear lever arms are interconnected by a leveling rod so as to coordinate the front and rear arms as force is exerted against one arm by power-operated means on the implement. During one phase of vertical movement of the implement as it is raised or lowered, the leveling rod is stressed in compression. The invention provides yieldable means in conjunction with the rod capable of yielding as to prevent or at least minimize bending of the rod in the event of over-stressing.