Hi All Posting again and I appreciate all the help Iv gotten on this forum Have a Cat336D (WRK00200) with 16,000 hours Working perfectly until 2 days ago the hydraulics starting working very slow after a few hours into shift on all hydraulic functions If switch off machine and let it cool down for 30 mins or so then you have full power to the hydraulics again for a while but then starts getting slow again Operators have noticed once the hydraulic oil temp gets around 40 degrees Celsius is when it’s starts to get slow No faults on ET and all pressures on panel seem to match the requirements Fitters think it may be the main pump starting to bypass from wear but I’m not so sure it would fail this fast
Looks like these machines are fitted with a flow control solenoid block that interrupts the flow control signal to both pumps. Not common to have both pumps fail at the same time so assuming that the pumps might still be ok, some possibilities could be... a setting issue on the monitor for single pump/dual pump flow control, stuck solenoid valve or blown orings on the solenoid valve, possible controller issue. with out doing pressure and flow tests I would remove and inspect the solenoid to start with then disconnect it when the machine faults and see if the speed of the machine returns in all the functions