Working on a daewoo doosan 140 solar. Customer had somebody replace rotary joint seals for a tracking issue but it was much the same afterwards. He called me i blanked the hoses before the joint and checked pressure i had full 340 bar. Reconnected the hoses and then blanked hoses down at travel motor when checked the pressures only have 300 bar 1 way and about 310 the other way so fluid has to be escaping in the joint. Took out the joint the seals looked ok none damaged but re sealed it to be sure. Stil the same. Has anybody ever seen a rotary to hairline crack or fail before?
How did the hard parts of the swivel look? Build quality of those machines was always kind of suspect.
Sounds like you are looking for zebras when you should be looking for horses.Check the case drain lines on the track motors.If the oil squirts out of them like a fire hose when you pin the tracks then you have a bad track motor.