A tillage machine (10) comprises a frame (30) having tillage tools supported thereon. At least one wheel arm (48) is pivotally attached to the frame (30) for up and down swinging movement relative to the frame about a first transverse axis. A walking beam assembly (40) includes a primary beam (54) and at least pair of ground-engaging wheels (64, 76) rotatably coupled to the beam at front and rear ends (58,60) thereof. The walking beam assembly (40) is pivotally attached to the wheel arm (48) for up and down rocking movement relative to the wheel arm (48) about a second transverse axis. A hydraulic lift cylinder (46) is operably connected between the frame (30) and the wheel arm for swinging the wheel arm up and down relative to the frame to raise and lower the frame relative to the ground. An abutment (106) is provided on said wheel arm (48) disposed to engage a stop (100) on the beam (54) in response to a predetermined amount of downward swinging of the wheel arm relative to the frame (30). The abutment and
