Bulldozer Komatsu D61EX-12 Hydraulic Main Control Valve Assembly Part Numbers: 723-25-10500, 723-25-10201, 723-25-10202 Common Faults & Troubleshooting Specific action is weak / not working: Stuck spool in that section, spool/sleeve wear causing internal leakage, damaged O-rings. First measure the outlet pressure of that section to diagnose. All actions are weak: Usually caused by insufficient main pump pressure or a failed main Relief Valve pressure setting. Check system