GEAR 2223904 - Caterpillar

3406B ( 7FB)Reference: Service Manual, Parts Book. Early production aluminum 8N9679 Governor Housings on 3406B Truck Engines used a machined bore for the governor control shaft. An 8N3945 Bushing can be installed to salvage housings with a worn outer bearing bore. This instruction describes the procedure and lists the tools for the installation of the bushing. Preparing The Governor Housing
1 Remove and disassemble the governor; see the Service Manual.2 Clean the governor housing thoroughly, especially all contact surfaces.3 Install the governor housing into a suitable holding device (bench vice, etc.).4 Install FT1951 Bushing into the FT1950 Fixture. Install the fixture with the two 1B2713 Bolts on the governor housing.Reaming The Housing Bore
1 Use an electric drill with FT1949 Reamer (1) to enlarge the bearing bore to 18.821 0.013 mm (.741" .0005").
Use kerosene (2) on the reamer for lubrication. Feed the reamer slowly and smoothly into the bore. Feed speed, reamer rpm, and the amount of lubrication during the reaming process will have an effect on the final size and finish of the bore.
2 After the bore has been reamed to the correct size, remove the two 1B2713 Bolts from the governor housing. Remove the FT1950 Fixture and FT1951 Bushing. Thoroughly clean all drilling chips and other debris from the governor housing.Installation Of 8N3945 Bushing
1 Put an 8N3945 Bushing onto the driver with the chamfered side of the bushing pointing away from the driver. 2 Install the 8N3945 Bushing (1) into governor housing bore (A) to a depth of 12.5 1.0 mm (.492" .039").3 Lubricate the bearing bores and install the control shaft. The control shaft must turn smoothly without binding.4 Assemble and install the governor; see the Service Manual.