hi i have a komatsu wa380-6 , the boom drops about +/- half a meter. It appears to drop as soon as the ride control becomes active , it will drop once with a full bucket load and then carry on to work as normal . Ride control works as it should , i have checked the accumulator pre-charge pressure and it was all ok. The boom cylinders do not drop at all when the ride control function is switched off, i completely discharged the accumulator to check for oil by-passing into the nitrogen side and did not find anything wrong. After recharging the accumulator i disassembled the ride control spool valve and it all seemed to be in good condition, after assembling it all back together the problem went away for a day. I checked the pre-charge pressure again and it was where it should be +/-46 bar at 15 degrees Celsius. The komatsu dealer had a look at it before i did and also could not figure out the problem. Has anyone come across this problem before? Any help or advise would be much appreciated. Thank you.
Found the problem today, had a small screen (check photo) stuck between the pressure reducing valve poppet and spring on the accumulator charge valve. I could not get any pressure reading at the charge valve test port and disassembled the charge valve. After correcting the problem, the pressure readings at charge valve was 1660psi. Hope this helps someone that comes across this problem.