Hydraulic Wheel Steering help

[rossny]

Hi, I need reference materials to learn about my new to me hydraulic wheel steering. Boat is early 80's english built sailboat, the wheel action is hard and may be leaking hydraulic fluid, it has a reservoir with a schreider valve for using a air pump for pressure. There is something labeled an octopus valve/pump for maybe for the auto pilot? Please help steer me to information to understand and maintain this system. None of the boat books I have go into this in any depth. Thanks all.