hi, not long ago I aquired a 84 mod Hitachi UH083. It has big manual levers for the main valve.
Great machine

I use it on a smal holding, doing trences now, preparing for heavier flooding.
Have some problems with leaking swing gear. Gear oil came out of the side, second time.
First time, got it out and replaced the bottom seal. Now the same happend again, but no after a day or two of sitting, hydr oil came out the oil stick of the swing gear. Think it is hydr oil. Problaby the seals on swing brake/swing motor that have blowned?
At the first instinance, the seal in the swing gear was oval, and no gear oil in the gear, just greas (bush repair?). After filling up with gear oil, it started leak after some 10s hours.
See that some owners bleed air pressure after working. I have never checked air pressured if it's too high (safety valve is rusty). The previous owner used the machine as a harvester, with a Valmet 955. With open valve on hydr tank to insure minimum return-pressure in order to maximum flow to the harvester head, i think. Anybody that see the connection to thees problems?