Tractor Repair: hydraulics hookups, hydraulics system, diameter cylinders

Question
I have a m-farmall I need to know the hose hookups on the hydraulics system. There are 2 places on left sitting in seat. There are 2 on the right and a plug on the bottom of the pump pan and the filler cap on top. main supply and pressure to cylinder and return to pump resovoir.

Answer
Hello,

  If this is a regular M and not a Super M, they were originally made for single acting one-way hydraulic cylinders only.  There was a 2 way valve that could be added, but I have never worked on one of those, I've only seen them.  On the original style, there were 2 outlets on the left, the front one for front cultivators, and the rear one which lifted the rear cultivator only after the front cultivator was raised all the way up.  For other applications, the rear one was not used.  The one on the right side shared a common outlet  with the front left one, so they lifted equally on both sides for a loader, etc.  There was no return line, since a one way cylinder just pushes the oil back into the tractor on the same hose when it retracts.  With the 2 way add-on valve, the right one was hooked to a separate valve under the fuel tank, and there was another control lever for it besides the original control rod.  You could run a 2 way cylinder on this valve, and the return oil line was teed in under the filler cap to return to reservoir.  The capacity is 6 qts. of #30 engine oil.  Don't use hydraulic oil.  The maximum pressure on these tractors was only 750 to 850 psi, compared to modern tractors that have 2400 to 3000 psi, so they don't have much lift capacity unless you have large diameter cylinders.

                         Arnie