Examine the right side of the lid, there should be a plugged outlet, just in front of the lifting arms axle, it's angled and 3/8 in size, this is where you will take oil out to a selector valve, you will need one with one inlet and two outlets.
But first things first.
You will need to remove the existing valve chest to get to a pipe that's sticking out right next to the ram cylinder bore, look at http://www.fordson.se/phpBB2/viewtopic. ... c&start=15 for pictures.
You will need to either tap the inside of the pipe and plug it with something(M14 insex set screw I think would fit) and a high pressure whitstanding sealant, or you will need to manufacture a steel rod with the same O.D as the pipe with grooves for the seals at both ends. This part plugs the original pressure pipe to the valve chest.
Once that is done you can put it all back together, connect a hydraulic pipe or hose to the angled outlet just in front of the right lift arm and route that to earlier mentioned selector valve, one of the outlets on this selector valve must be routed to the "jack tapping plug" on the original valve chest, otherwise you will not be able to use the 3-point hitch anymore. The second outlet on the selector valve is where you connect your hydraulic valve rack for whatever equipment you will use with the tractor, this rack of valves MUST have a shock valve set to a release pressure somewhere in the vincinity of what the one in the original valve chest is set to, otherwise you will have no pressure limit and that could lead to your hydraulic pump cracking or other nastier accidents.
Now connect any auxiliary hydraulic equipment to your valve rack and use the selector valve to choose if you will use the valve rack or the built-in original valve to raise or lower the 3-point hitch.
Note that you cannot maneuver both the 3-point hitch and your aux hydraulics at the same time, this modification will however allow you to leave the 3-point hitch in any desired position while using for example a front end loader
Pictures and information on this courtesy of Jesper and Defender at fordson.se