Hi there, i have a old digger ( 1986) MS040 ( mitsubishi or Cat ) that over the last year one side track is getting harder to move. It started out when you moved the leaver to go forward it would move forward a faction and then you would hear a Psuu coming from the back ( assumed it was bypassing hydro oil ) and the track would stop. however if you moved both tracks at the same time it works fine.If you lift that track in the air it rotates fine. Is there such a thing as a pressure releave valve in each Individual bank of the control valve, that just needs to be increased in pressure? or does it sound like a oring problem ? any ideas would be great. thanks des
Sounds like the seals in the swivel joint are worn out. The reason why both tracks move at once is the pressure in the left side is keeping the right side from bleeding in
thanks for that, i am not sure what you mean by bleeding in?? and does this explain the pshuee sound from the back ( both sides tracks only move when both levels are pulled.) thanks
It may or may not but a swivel reseal is cheap and easy and is most certainly needed on such an old machine and it is hard to diagnose the tracking if the swivel is leaking.
Des, the travel spools on those excavators are float center(both directional ports are open to drain in hold). If the swivel seals are leaking and you move one track the oil can leak to drain through any of the 3 other work ports. If you move both tracks the leakage has to leak into at least one other port that is pressurized. Also it takes 5 times as much pressure to drive one track to turn as it does to drive each track to travel straight. Difficult turning on a hard surface with warm oil is good test of a swivel. Later Bob