TM   10-4930-250-13&P CHAPTER    4 UNIT   MAINTENANCE Page Section  I Lubrication    Instructions   ..................................................... 4-1 4.1 Lubrication ............................................................ 4-1 Section  II Service  Upon  Receipt   ...................................................... 4-2 4.2 Unpacking   ............................................................. 4-2 4.3 Inspection ............................................................. 4-2 Section  III Preventive  Maintenance   Checks and  Services  (PMCS) .................................. 4-3 4.4 General .............................................................. 4-3 4.5 Leakage  Criteria ......................................................... 4-3 4.6 PMCS  Procedures   ........................................................ 4-4 Section  IV Unit  Troubleshooting    Procedures   ............................................... 4-6 4.7 Troubleshooting ......................................................... 4-6 Section  V Unit  Maintenance    Procedures ................................................. 4-8 4.8 Fuel  Delivery    Equipment   Maintenance ........................................... 4-8 4.8.1 Replace  Two-Inch   Valved   Unisex   Coupling ........................................ 4-8 4.8.2 Replace  Three-Inch   Unisex   Coupling ........................................... 4-10 4.8.3 Replace  Unisex   Coupling   Dust  Cap ............................................ 4-12 4.8.4 Replace  Unisex   Coupling   Bumper ............................................. 4-14 4.8.5 Replace  Unisex   Coupling   Lugs   ............................................... 4-16 4.8.6 Replace  Three-Inch   Unisex   Coupling   Dust  Cap  Lugs   .................................. 4-17 4.8.7 Fuel  Hose  Assembly  Repair   ................................................. 4-19 4.8.8 Replace  Two-Inch   Non-Valved    Unisex   Coupling .................................... 4-23 4.8.9 Repair  Two-Inch    Non-Valved   Unisex  Coupling ..................................... 4-25 4.8.10   Replace  Auxiliary    Pump   ................................................... 4-27 4.8.11    Clean  and  Replace  Auxiliary    Pump  Inlet   Components ................................. 4-30 4.8.12    Replace  Auxiliary    Pump  Rotor  Vanes   ........................................... 4-32 4.9 Special  Instructions   for   Administrative    Storage ..................................... 4-34 Section     I.    LUBRICATION INSTRUCTIONS 4.1     LUBRICATION. Lubrication    by  unit  maintenance  is provided   in  TM   10-4320-351-14. 4-1