The issue I'm having is, when I start out with the arm extended out and I retract/lower the arm, it delays for about 2 seconds once the arm gets to a vertical position. From my understanding, the arm uses gravity to bring the arm to that point (unless there's resistance from digging) and then the load sense will kick in and allow hydraulic pressure to continue the movement. The time in between it using gravity and hydraulic pressure is too long. I was curious if anyone has ever come across this and could give me some ideas on what it could be or where to look. So far I've: -Checked the load sense sensor -Removed and checked the arm control valve and checked all springs and ports within the valve. -Checked the pressures and they seem fine except for during that few moments of hesitation. -All filters have been replaced -I haven't seen any bent or kinked hoses Any ideas would be helpful. Thank you!
One common cause can usually be linked to a lack of hydraulic flow to the function, the Arm drops due to gravity however the base side of the arm cylinder has created cavitation as not enough oil is being supplied, the arm stops its movement once vertical and continues to retract once the base side has enough oil to continue the movement. A lot of excavators can use a regeneration feature on the arm/dipper retract function to increase its cycle speed while reducing the overall amount of flow required to complete the movement. If you can give a serial number off the machine then some of the members on this forum should be able to assist you if you need any technical information to help with your diagnostics. Best regards
Thank you. The serial number is B4GR14604
I will try and see if I can find some technical information to help with your diagnostics.
Here is some information that may help. I would suggest looking back at the pressure compensation spool in the control valve arm section and check to see that there are no defects such as a worn or sticking spool or blocked orifice if applicable. If you need any further information, send me a message and i will try and help where possible, otherwise other members will most likely reply to your posts and try to help you with fixing the issue. Best regards
Here is some information that may help. I would suggest looking back at the pressure compensation spool in the control valve arm section and check to see that there are no defects such as a worn or sticking spool or blocked orifice if applicable. If you need any further information, send me a message and i will try and help where possible, otherwise other members will most likely reply to your posts and try to help you with fixing the issue. Best regards