Komatsu WA380-6 Operation & Maintenance Manual page 290

MAINTENANCE
7. When installing, tighten until the packing surface contacts the seal surface of the filter holder, then tighten it 3/4
of a turn.
If the filter cartridge is tightened too far, the packing will be damaged and this will lead to leakage of fuel. If the
filter cartridge is too loose, fuel will also leak from the packing, so always tighten the correct amount.
8. After completing replacement of fuel filter cartridge (1), bleed the air from the system.
For details, see "PROCEDURE FOR BLEEDING AIR (PAGE 4-53)".
9. After completing the air bleeding, start the engine and check that there is no leakage of fuel from the filter seal
surface. If there is any leakage, check the tightening condition of the filter cartridge. If there is still fuel leakage,
repeat Steps 1 - 3 to remove the filter cartridge, then check the packing surface for damage or embedded dirt.
If any damage or embedded dirt is found, replace the cartridge with a new part and repeat Steps 4 - 8 to install
it.
PROCEDURE FOR BLEEDING AIR
1. Fill the fuel tank with fuel.
2. Open the engine side cover on the right side of the chassis.
3. Loosen and pull out feed pump knob (1) and move it forward
and backward.
The plug on the side surface of the fuel pre-filter head does
not need to be removed.
Keep moving knob (1) until it becomes heavy.
4. After bleeding air, push in and tighten knob (1).
SERVICE PROCEDURE
4 - 53