I have an old Versatile 876 tractor that we still use for some tillage and planting with an air seeder.  Great tractor and have had few problems with it.  The problem we are having now is excessive internal bypass in the hydraulic valve block.  For functions requiring high pressure like folding you have to wait until it cools off for the oil to thicken enough to generate enough pressure.  We need to take off the block and replace all the seals and o-rings.  In addition we need to replace some of cables that are hard to work and we have an issue with one of the valves.  I saw this the other day from Summit and it got me to thinking maybe I could just change out the whole system to electric control like a modern tractor.  Little expensive but given the work we have to do to our existing system it would not be that much more.  Has anyone done this on an older tractor??  I need to do a little more homework to make sure I get the right stuff for what I need.