This video shows the manufacture of a large and strong hydraulic press using a dimamo drive, here is the sequence:
The dynamo turns the oil pump towards the oil control valve, then from the oil control valve it flows into the hydraulic tube. The oil control valve is useful for directing where the oil will be put into the tube, when the oil will be put into the tube. If oil enters the top tube, the hydraulic shaft will go down, and if oil enters the bottom tube, the hydraulic shaft will go up