Hi All. New member here but because of my dad I've been around a couple of red tractors all my life, namely a 560 diesel Farmall with the factory style turbo kit on it and a 1206 Farmall. My dad used both of these to hobby farm from the late 60's through the early 2000's. Now that he's retired he still farms about 10 acres for fun. Back in December 2019 he bought a 460 diesel to go with these two but it was non-running. We did get it running somewhat after getting the fuel pump and injectors rebuilt but it didn't run very good so it ended up getting a complete engine overhaul. What little we did have it running we noticed the Hydra-Touch hydraulics were slow and the power steering nonexistent so while the engine was out we drained the hydraulic oil, put in a new filter and replaced the power steering pump. Now that the engine is all done and running nicely he's wanting to use it some but as the title here says, the power steering and hydraulics are still weak. Besides the old I&T service manual he's had for years for working on the 560, I purchased some reprints of the factory IH service and parts manuals for the 460. Besides looking through them and looking on here I still haven't found what may be wrong. As to what has been done we've gotten this far: new fluid, new filter, new power steering pump (with new O-rings to mate it to the Hydra-Touch pump), replaced the suction tube that is on the main hydraulic pump (seal was bad on the old one, it didn't seal to the machined recess in the clutch housing), new O-rings where the pumps mount to the plate on the side of the clutch housing, new O-rings for the pressure lines coming from that plate, new main pressure hose from the pump to the Hydra-Touch valves, opened up the relief valve finding nothing really wrong with it but still did new O-rings and gasket (including the O-ring on the safety valve inside it) and new gasket for the filter housing plate.
So far this has gotten us to have nothing below 1500 RPM and slightly better from that RPM on up. Although we don't have the flow rater setup the IH service manual calls for, we have checked for pressure at the pump outlets. Steering is around 500 psi (over 1500 rpm) and spikes to 2000 psi when steering is at full lock. Hydra-Touch has little to no pressure below 1500 rpm and won't move the fast hitch, over 1500 rpm will move the hitch but only shows 150 to 200 psi max. We compared this to his 560 and it has around 500 psi at idle for both systems and peaks around 1300 psi, which from what I've read is normal. From what I can tell the Hydra-Touch and power steering only share the filter, inlet tube and reservoir so I keep leaning towards something wrong on the suction side since both systems are affected. The only things on the suction side we having messed with are the suction tube in the transmission housing and the O-ring for it where the clutch and transmission housings meet. I took the belt pulley drive plate off and the suction tube isn't loose in the transmission case. There are no huge visible leaks where that much oil is coming out of either system either. This tractor did set dormant in a barn for who knows how many years but from the pump housing the relief valve being apart there didn't seem to be any crap in the system. I haven't pulled the cover off the Hydra-Touch pump yet to look inside it, but I would think the steering should work being a new pump, a pump we got from the same place we got one for the 560 3 years ago.
I'm at a loss right now, other than splitting the tractor again and pulling the clutch housing from the transmission to check that O-ring and pulling the transmission top cover to check the suction tube, both are very major jobs. So hopefully one of you might have some insight as to something we may have missed before we start on something like that?