RING-RETAINING 3K3138 - Caterpillar

Fuel leaked or spilled onto hot surfaces or electrical components can cause a fire. To help prevent possible injury, turn the start switch off when changing fuel filters or water separator elements. Clean up fuel spills immediately.
Use a suitable container to catch any fuel that might spill. Clean up any spilled fuel immediately.
Do not allow dirt to enter the fuel system. Thoroughly clean the area around a fuel system component that will be disconnected. Fit a suitable cover over disconnected fuel system component.
Illustration 1 g01186208
Left side view of engine
(1) Fuel priming pump (typical example)
Illustration 2 g01326675
Detailed view of the fuel filter and priming pump
(2) Priming valve (if equipped)
(3) Air Purge If the fuel system runs out of fuel or if air is introduced into the fuel system, either of the following procedures may be followed. If necessary, fill the fuel tank with clean diesel fuel.Using the Engine to Prime the Fuel System
Turn the ignition switch to the "OFF" position.
Turn the priming valve (if equipped) to the Prime position.
Purging air from the fuel system requires the air purge to be opened three full turns. Open the air purge. Do not remove the screw.
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.
Crank the engine for 30 seconds. Use a suitable container to catch the fuel while you crank the engine. Allow the starting motor to cool for 2 minutes. Note: Most of the air should be purged from the system after four or five cranking cycles.
Repeat Step 4 until the engine starts and runs. If the engine runs rough, continue to operate the engine at low idle until the engine runs smoothly.
Observe the air purge. When a small drop of fuel appears at the threads of the air purge, close the air purge. After the air purge is closed, tighten the air purge. Note: Failure to tighten all fittings could result in serious fuel leaks.
After the engine has operated smoothly for 30 seconds, turn the priming valve to the Open (Run) position. Note: The life of the injectors may be shortened if the priming valve is left in the Prime position.
Clean any residual fuel from the engine components.
Once the engine runs smoothly, stop the engine. Turn the ignition switch to the OFF position. Using the Fuel Priming Pump (If Equipped) to Prime the Fuel System
Turn the priming valve (if equipped) to the Prime position in order to prime the fuel system.
Purging air from the fuel system requires the air purge for the fuel filter to be opened three full turns. Open the air purge. Do not remove the screw. Note: Failure to tighten all fittings could result in serious fuel leaks.
Clean any residual fuel from the engine components.
Continue to operate the fuel priming pump until a strong resistance is felt. Listen for an audible click from the fuel manifold. The click will indicate that the valve has opened and the fuel system is pressurized. Lock the