the one for the power steering and brake lines go to is the one i'm speaking of. It may be refered to as the auxillary hydraulic control valve or steering priority valve. Without a manual to look in to see what exact terminology they are calling this i do not know for sure.
No manual on hysters website, the unit is too old.

look on that valve assy though and see if there are any check valves on it, or plugs that may contain a check valve.

chances are you will find one stuck or broken.

no direct lines connecting the two? it has to be getting its fluid from somewhere.