FILM 1957057 - Caterpillar

Introduction
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.The new fuel priming instructions helps to prevent failures of the injector plunger spring and injector tip from air being trapped in the fuel system after component replacement.Inadequate priming can result in air being present in the low-pressure fuel system and inside the injectors. Attempting to start the engine without adequate priming results in an overload condition on injector plunger spring and tips, causing early hour failures.
Illustration 1 g06264933Installation Procedure
Illustration 2 g06215607
Damaged plunger spring
Illustration 3 g06215611
Cracked injector tip
The proper procedure for priming the fuel system can be found below:
Locate the fuel priming pump.
Operate the priming pump plunger to fill the final fuel filter. The fuel filter will be filled once there is resistance felt.Note: The priming pump may need to be pumped 25 times or more to fill the fuel filter. The fuel priming process may take up to 75 pumps to fill the fuel supply passage.
Push and tighten the plunger in a counterclockwise direction by hand.
After the fuel system is pressurized, crank the engine promptly.