Aliquantus,

There is a flow control valve that is supposed to ensure the steering has a constant flow of hydraulic oil. There could be a failed or sticking valve inside. Also, the hydraulic pump has the relief valve inside for the steer system. Connect a gage at the pump and turn the steering wheel until it stops. If you have no pressure, there may be a problem in cylinder, steer control unit or hoses. Will the steering work any if you run the tilt valve while trying to steer? Good Luck.