To change hydraulic oil the manual says to drain the tank and that the hydraulic oil and hystat oil are the same. The capacities(refill) section says hydraulic tank holds 37 litres(9.8 USgal) and the hydraulic system holds 84 litres(22.2 USgal). Is the hydraulic system mean all hoses, lines and hydraulic tank or just hoses, lines and the tank is separate. I would like to change ALL the hystat/ hydraulic oil. Is there another drain to drain the hoses, lines and pumps? Maybe take off a panel/skid plate under the dozer to drain the entire system? If so the manual does not state this. Thanks
No,no no, you don't wast to drain hoses, pumps and motors. The only drain is the one on the hydraulic tank and the filters are in the right side door. That is all you have to do to keep it serviced. You don't want to run the chance of getting air in the system as it will damage your pumps and motors. You would be starting them dry/no lubrication and this is what eats up all of the moving parts. The only other thing to keep is serviced is pulling a sample on your old oil and sending it in. This way you can get advanced notice before something blows up.
Thanks for the info, sounds like an easy oil change. Still seems strange I won't be changing all the oil.
The oil change frequency recommended in the manual takes account of the fact that you are only changing about 44% of the total system volume.
I don't mind changing oil frequently as oil and filters are cheap compared to repairs and downtime.