Dear friends In our Cat excavator 375 L (2002) some times the all joystick getting hard to operate. We have changed hydraulic oil and filters, checked the pilot pressure, which is ok. Can any one advice me further. Regards
Do you mean hard to move the lever or not very responsive to the control movement? Later Bob
Ya, its hard to move the lever
Could be a restriction in the pilot return to tank line from the joysticks.
I think there is no restriction in return line because it occurs for some time and when keep the machine idle for a while then it becomes normal.
Those symptoms could indicate a restriction in the pilot return to tank line from the joysticks, because if there is a restriction then idling the machine for a while (i.e. not using the joysticks and generating more return to tank oil) will permit the return oil that has accumulated in the pilot control valves under the joysticks to pass back to the tank despite the restriction, thus removing the problem - albeit temporarily. I think you should be looking at that return to tank line to be honest, even if it does nothing else other than rule it out as a potential cause of the problem.
we checked the pilot return line and it is clear. But we found the accumulator is damage, waiting for new one. Let us see.
so how was it? any updates