I’m having hydraulic problems with a cat 559 C knuckle boom loader. The swing is slow until I use another function such as boom up. Serial Serial #KB400249. i wanted to know if anyone could help me locate the priority valve or resolver valve I’ve heard that could be my problem
With Negative Flow Control, I don't think there are resolvers.
Is there a priority valve I could look at cleaning on this machine
It sounds like the rear pump has low flow output. When you activate the boom function, you are engaging the front pump which lets the swing rob some flow from it and speeds it up. I would do the cycle speeds test, record all numbers and the. go through and run main relief tests and line relief tests on all circuits and record all results. You will also probably need Cat ET to monitor the machine ECM parameters to see how the pump is being controlled. Would also be beneficial to get a flow meter hooked up on both pumps to compare the actual output to spec. Front pump is 64 GPM and the rear pump is 47 GPM.