Hoping someone here can point me in the right direction. I bought this tractor not running a few years ago, as a project, and I've hit a road block that has me stumped. The tractor is the smaller 3 cylinder diesel engine, pre-266,000 serial number, open center hydraulics. After running the tractor for 20-30 minutes, the hydraulic lines running to and from the power steering and pressure relief valve get burning hot. If I continue to use the tractor, eventually the steering column and/or the pressure relief valve being to squeal. What I find puzzling is the heat seems to originate on the low pressure return line (Key 27) from the relief valve that T's back into the charge pump line. I originally suspected the steering column, as a high pressure leak seems to be a common issue but the steering wheel seems to work fine, no oil out the top, very light to turn in both directions, and does not creep on its own. So, I tore apart the relief valve. The valve (Key 9 and seat 10) was slightly marred up and might have been the issue, so I bought a replacement, and the problem is still present. At this point I'm out of ideas as to what the issue could be. Could it still be a high pressure leak inside the steering column causing the heat in the return line from the pressure relief? Unfortunately I don't have a pressure gage to test the relief pressure, does anyone have recommendations for building one or purchasing one? Any ideas would be appreciated, I've been a long time reader, first time poster.