Our '75 Whitby 42 has a pump plumbed into the hydraulic steering system. I believe it's a Centrec?. I assume it's a reversing pump for an autopilot. The original owners had a wind vane and a subsequent owner (Lew and Deb?) installed a wheel pilot so I don't think that pump has ever been used. Was that pump a factory option?
Going down this coming weekend and plan to put some juice to it and see what happens.