The main reason that a 980C Caterpillar diesel engine will need the fuel system bled is due to air getting into the fuel system. Air will generally get into the fuel system if the fuel filter is not properly replaced. If the new fuel filter is not completely filled up with fresh diesel before installation, air will get into the fuel system and prevent the engine from cranking. The fuel system must be bled to remove the air and to crank the engine. The fuel bleeding process for the 980 loader and most other diesel engines requires the same method.
Loosen and remove the fuel filter with a fuel filter wrench. Fill the fuel filter completely full of fresh diesel. Wait a few minutes for the diesel to absorb into the fuel filter and finish filling the fuel filter up with diesel. Re-install the fuel filter to the engine and tighten the filter with the filter wrench. If the fuel filter housing has a rubber primer button, mash the primer button in and out five or six times to fill the lines full of diesel.
Barely loosen the lock nut from the fuel line that is attached to the number one fuel injector with an open-end wrench.
Crank the engine over with the key until the air coming out of the loosened fuel line nut turns into a steady flow of diesel around the fuel line nut. Re-tighten the fuel line nut with the open-end wrench. Re-tighten the fuel line nut with the open-end wrench.
Move to the number two fuel injector and barely loosen the lock nut on the fuel line that is attached to the fuel injector with the open-end wrench. Crank the engine over until the air coming out of the loosened fuel line nut turns into a steady flow of diesel around the fuel line nut. Re-tighten the fuel line nut with the open-end wrench.
Barely loosen the remaining fuel line lock nuts one at a time and crank the engine over until the air turns into a steady flow of fuel around each fuel line nut. Re-tighten the fuel line lock nuts. Crank the engine after the last fuel line has been bled. The engine should have no problems cranking now.
