Our dozer blade just stopped nearly all at one. Replaced pump few months ago when it did it then. Used less than 20 hrs here an there since then an now that we wanta use it again it started same thing again. Well I have replaced the resolver orings in control valves months ago , there were orings blown out back then. So now I plugged my gauges into pilot line disconnect test fittings An read hardly any press. So I pulled valve body back out An rechecked resolver seals. They were all still in place. So since valve body was out I went ahead An replaced orings again with regular orings outta my box ( they were regular orings I installed an they weren't the red nor white ones). So I reinstalled valve body back to machine an it still blade barely moves Seems to help doing 2 functions at a time. An at times when it does bottom out a function my gauge will read round 2000 psi area an sounds low when plugged into main valve body test port. Oil is a Lil milky An filter don't seem to be collapsed like it has in the past. Hopping it's not pump failure again
Did you check the pressure relief valve , I have had quite a few times when something gets stuck in it holding it open causing a lack of pressure .
Milky oil is sign of water, water also makes steam when heated or becomes compressible fluid mixed with hyd oils. Need to correct that as well pull and check the relief.
Did you change pilot or main pump and witch system has low pressure ?
We have replaced main Hyd pump recently an it went back to work then let it sit for months an now have barely any Hyd response
Sounds like the pump is not upstroking
Did you look at all hydraulic filters for metal