HOSE 7C7705 - Caterpillar

All Caterpillar Industrial, Marine And Generator Set Engines With New Scroll Fuel SystemsIncorrect installation of the O-ring seals and bushings, that hold the fuel injection pumps in the fuel injection pump housing, can cause fuel leaks. The O-ring seals are used to keep the fuel, at transfer pump pressure, from leaking out of the fuel injection pump housing around the bushings.
Use the appropriate Service Manual, Disassembly and Assembly module in addition to the information that follows for the correct installation procedure.
A. Turn the fuel injection pump camshaft until the lobe of the camshaft is down for the pump that is to be installed. This will make it easier to compress the pump return spring when the pump is installed in the fuel injection pump housing. See Illustration 1.B. Be sure the fuel injection pump is completely seated in the fuel injection pump housing when the O-ring seal and bushing are installed. Because of higher spring force, the 6V7050 Compressor Group must be used to seat the fuel injection pumps in 3406 Engines with new scroll fuel systems. See Illustration 2.C. Tighten the bushing, with the pump firmly seated in the housing, until the bushing contacts the pump. Then remove the tooling and tighten the bushing to the correct torque. Failure to have the fuel injection pump correctly seated in the fuel injection pump housing when the O-ring seal and bushing are installed, can cause the O-ring seal to be damaged. The result can be a fuel leak.
Illustration 1. Components of a fuel injection pump group.
Illustration 2. 6V7050 Compressor Group used to install fuel injection pumps in the fuel injection pump housing.