I have had this tractor since 1981 and it came with a heavy plow on the front that is raised by a cable going back to the arms on the 3pt hitch. I use it for plowing snow and it is getting weak. When I first start it it works OK lifting the plow but after 20 minutes or so it gets progressively weak and then stops being able to lift. I can let it sit for a few hours or more and it repeats the same scenario. The weather here lately has been mostly around in the 20's along with down to zero or below. I have an old shop manual and am going to remove the PTO shift cover to look for turbulence around the relief valve or leaks. Next step will be to check the hydraulics pressure at the lift cover plug. Already borrowed a 10,000 PSI gauge and fittings. Per the manual, it should be around 2000 PSI and if it drops within 10 seconds will need to replace pump. I am looking for any advice and also recommendations where to go for a new pump and whatever else is needed. I believe it is still the old vane type now.