Rear mounted attachment with single acting cylinder

A trailing attachment for a deep tillage implement is supported from the implement frame by transversely spaced four-bar linkages extending rearwardly from the frame. Single acting hydraulic cylinders are pressurized to lift and adjust the attachment. A breather plug and a U-shaped hose allow air to be pushed from the rod end as each cylinder extends. To lower the trailing attachment, an SCV is moved to open the base ends of the cylinders to the return line of the hydraulic system, and the weight of the attachment moves the tools into ground engagement. If vertical lifting force exceeds attachment weight during operation, air is pushed out through the breather plug and a vacuum is drawn in the base ends so the attachment can lift to avoid excessive forces, even if the SCV is in neutral and blocking fluid flow into the base ends.