1989/07/24 Caterpillar

3500 Family Of Engines;
D11N, 776B Tractors;
777B, 785, 789 Trucks

Description of Change: Several changes have been made to improve the retention of the bottom bearing in the control rod assembly used in the fuel injection control groups used in the above engines and machines. These improvements include:

... Heavier staking is used to retain the bearing outer race in the yoke end of the control rod.

... Improved assembly process and tooling reduce the side loads on the bearing while assembling the pin which fastens the lower end of the control rod assembly to the lower lever.

... Bearing improvements provide added side loading capability between the inner and outer bearing races.

These improvements will help prevent separation of the bearings and loosening of the bearing in the yoke of the control rod assembly.

Location of the improved 1N4679 Control Rod Assembly in the fuel injection control groups.

At engine overhaul or during and engine repair in which the control rod assembly/assemblies are removed on and earlier engine, Caterpillar recommends to inspect the lower bearing. Do not reuse any control rod assemblies if the bearing can be moved in the yoke, or if the there is more than minimal endplay between the inner and outer races of the bearing (new bearings have minimal endplay).

Adaptable To: The part number of the improved 1N4679 Control Rod Assembly has not changed. The improved 1N4679 Control Rod Assembly is in effect as shown in the chart.