Air is removed from an hydraulic system for an agricultural implement supporting a plurality of gangs of disk blades extending generally laterally relative to a forward travel direction. The implement has carrier frames pivotally connected to wheel assemblies for controlling the height of the carrier frames relative to the ground through hydraulic actuators acting on the wheel assemblies. The hydraulic control unit enables independent and individual control of each actuator. An electronic control unit (ECU) controls three way valves associated with each actuator so that they may be operated in unison or individually. Hydraulic fluid is passed through the most remote actuator first and then actuators closer to the hydraulic control unit to remove air.
