Komatsu D155AX-5 Bulldozer Main Control Valve Part Numbers 723-64-11100, 723-64-11101, 723-64-11200 Common Faults & Troubleshooting Specific action 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 weak: Usually caused by insufficient main pump pressure or failed main Relief Valve pressure setting. Check system pressure first before disassemblin