Started last year. When machine is cold, swing and left track would not function untill machine warms up then normal operation. I learned I could move the machine while cold by hold swing on while operating both track controls (must bypass through straight travel valve?). Now it is starting to lose HYD power when warm on that same pump, I can feel oil bypassing when I track left or start to swing and the "make up line" hose pulsates on the top of the swing motor. I have the manual but is does not list this problem, of course. The manual shows a common swash plate for both pumps. So my first guess is the relief valve in the pump. I going to try to switch the output hoses from the pump and see if the problems switch to other functions, the I can isolate the pump as the problem? Any help would be greatly appreciated. This is a gray machine and my manual is for a US machine, as far as I can tell it looks the same. Thanks in advance
I would question if the swing joint seal is starting to let go.
Not the svivel, I think one half of your pump is feeling sick and just as you suggest a good way of finding out is swapping the outputs.
Not sure if they operate in the same way but I've had this problem on my E300B, it had a worn priority valve on the pump which would jam and cause the same symptoms you're having. It's easy to take off and inspect, just a thought.
just an update. I did switch outputs and the problem went to other functions. After calling cat tech support I was shure I had a broken spring, that holds the pistons to the swash plate. I have the manual so I carefully took the pump apart and it looked clean and in good condition. I could not find any problems. The next day I was ready to reassemble it and noticed an a small wear spot on the brass backing plate, away from the slots where the oil is pumped from the pistons. I took a guess that this may slightly hold the rotating group from the plate. $200.00 for an 8oz piece of machined brass and another $200.00 for the coupler that drives the pilot pump, I reassembled the pump. Instanly the pump worked perfectly and I was back in service.