190xt power director questions

Hi I have a 1970 190 xt that we bought this spring. So far I have done a few minor repairs, changed all fluids and filters, and have maybe put 50 hours on it. When we bought the tractor, it had two hoses and gauges that went from the check ports on the power director valve up to the floor plate. I put some new gauges in them and checked drive pressures, and have been watching them since I’ve been running the tractor around. The pressure is a around 270 psi with a 5 psi plus minus bounce, and a slight drop when I turn the wheel in either direction for just a second. The steering has always been a little stiff, and the other day while disking, the steering got tighter, and I lost some pressure on the pd, bringing me down to 200. Taking advice I’ve read on this forum, I cleaned the flow divider on the pump mainfold and the pressure relief also. The steering became effortless, put the pd pressure didn’t change. I shimmed the pd to bring it up to 300 psi @ 1600 with cold oil ( this a manual pto tractor). When you work it and get the oil heated up, the pressure drops to 275 with the same 5 psi plus minus bounce and slight pressure drop when you turn the wheel either way By the way I’m using Mobil 424 hyd fluid in the hydraulic system. I checked the specs and it’s supposed to meet or exceed power fluid 821. My question is, am I working about nothing here? Should I just be happy with where I’m at with those pressures, or should I put one more shim in to raise the pressure just a bit more to compensate for the lost pressure with hot fluid? Thanks to everyone that posts information on here. I’ve owned a few green ones but I’ve always wanted an allis. I’m enjoying it a lot. The advice on this forum is very valuable. Thanks for any replies!

No ever since I cleaned the flow divider out, it has been behaving pretty well and the power steering is still effortless. The pressure for the pd does drop when fluid is hot, but I think that could be just viscosity related. I chose the Mobil oil because Mobil has a good reputation in our area and is reasonably priced. I’m just wondering if I should throw in one more shim to account for the small pressure drops in the pd when I turn the wheel either way. Thanks for the reply!

I ordered some shims from Agco and got them last night. 3 more brought me up to 300 psi with warm oil and that lessened the pressure variation when turning the wheel also. I agree with you on not cheaping out on oil, the Mobil is good oil and about mid range price wise $60.00 for 5 gallons if it on sale at fleet farm. As far as the xt, so far so good. If everything stays the way it is, I’m just going to chase down some pesky hydraulic leaks and keep using it. It’s a very snappy tractor and a lot of fun to use. Would hate to be without it!! How do you like your 200? How long have you had it?