Assembly STEP 8. INSTALL HYDRAULIC CONTROL GROUP HYDRAULIC GROUP OPERATION (For additional reference see HYDRAULIC CONTROL GROUP ILLUSTRATION on next page) The hinge wheel disk harrow is supplied hydraulic oil from the tractor by a single pair of hydraulic lines. These lines attach to the top ports of a diverter valve mounted at the front of the disk. Depending on the position of the diverter valve handle, oil flows to one of two pairs of side ports on the diverter (selector) valve. When the handle is pushed to the position marked TRANSPORT CONTROL, as shown on the diverter valve decal, the 5 “x 12” wheel lift cylinders and 3” x 6” tongue leveler cylinder can be operated. With the diverter valve handle in this position the harrow wheels can be raised for plowing or lowered for transport. Important: The disk should be fully closed (i.e., both gangs parallel) before moving the diverter valve handle to the TRANSPORT CONTROL position. Attached to the diverter valve is a pressure locking valve (pilot-operated check valve) that prevents the wheels from drifting down when the disk is in the plowing position.
When the diverter valve handle is pulled to the position marked ANGLE CONTROL, as shown on the diverter valve decal, oil from the tractor will flow to the 4” x 32 “ angling control cylinder for “on the go” control of gang angle while plowing. Important: The transport wheels should be fully raised before moving the diverter valve to the ANGLE CONTROL position. The angle control circuit is protected from over pressure by a 1750 PSI crossover relief valve mounted to the inside of the front gang carrier pivot hinge. The DH4317 and DH4320 disk harrows require that the operator manually shift the diverter valve from ANGLE CONTROL (plowing) to wheel TRANSPORT CONTROL from outside the tractor. This prevents the operator from accidentally lowering the wheels while in the plowing position.
