So I have a kobelco excavator that I've owned for almost 10 years. Recently, the machine started to develop a hesitation or jitter in two functions, the stick out and the boom up. It does it in both cat and john deere pattern at the same place so I don't believe it's in the pilot system. I just changed the hydraulic filter and there was a ribbon that kobelco puts around the filter that was ripped off the filter. I was able to pull the ribbon out of the hole it came out of and it looks like none of the ribbon is missing so I don't believe it entered the hydraulic system. Pretty stupid to have a ribbon around the filter as I don't know what the purpose is. Anyways I'm going to get a service manual and try to diagnose this issue. I need some kind of schematic to see what's doing what. Anyone point me in the right direction or have a similar problem? I really hate to bring this think to the Kobelco dealer. Haven't had a good experience with them in the past.
Good day gland Could be air in the pilot system try bleeding, be a good idea to check the pilot pressure when you are using both functions. kind regards Uffex