Serial #DCH245R7NHE7K1143 Looking for some help with this excavator. It acts very weird when digging. If you reach out with the stick, boom down, bucket with teeth facing down and on the ground or pile you’re digging, start to pull the stick towards you and do not use the boom control while still pulling the stick in, the boom cylinders will raise up as you are pulling the stick in. Very strange issue and it makes it hard to dig. The machine currently has 2900 hours on it and the company I work for purchased the machine with 800 hours on it. The operators have complained about this machine not having enough digging power since they got it, I’ve been there for a year and change and just had the opportunity to run it in our yard digging out of a rock pile feeding a crusher and it definitely feels weak and you need to really work it to dig into the pile due to this weird boom/stick issue and I’m thinking it could possibly be a relief valve? They also switched the pilot lines from CAT controls to JD. Any help would be greatly appreciated.
The circuit relief for the boom up circuit could be bad. I'd check the hyd. pressures and go from there.
Thanks for the reply. Any idea of what pressures should be for the boom circuit?
I have listed here the possible causes of the symptoms as you mentioned in order of handling from easy to difficult: a)- Caused by relief valve of "BOOM-DOWN" (incorrect valve adjustment; clogged valve; valve damaged...). b)- The piston seal of the "BOOM" cylinder is damaged (can be easily checked by lifting the machine up by "boom down", turning off the engine then measuring the rod extension amount of the boom cylinder after 10 min).
Just wanted to update this. We got too busy and had the dealer come out and rake a look. They are fairly certain it is a damaged relief valve for the boom. Coming out later this week for a couple more pressure tests to confirm.