The part numbers for the Komatsu D155AX-5 bulldozer main control valve are 723-64-11100 723-64-11101 723-64-11200

723-64-11100, 723-64-11101, 723-64-11200

• 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 disassembling the valve.
• Erratic/jittery movement: Stuck spool, fatigued springs, unstable pilot control pressure, contaminated oil.
• Oil leakage: Aged O-rings on valve body joints and spool seals, causing external seepage or internal leakage.
• High oil temperature: Excessive internal leakage in the valve group, abnormal throttling.

• Minor faults: Clean the spool, replace the O-ring seal kit, lap the spool.
• Scored spool/worn sleeve: Replace the spool parts or the complete valve assembly.
• When ordering: Confirm the specific sub-model and the original old part number.