Generator Set Front Bearing Oil Leaks Caterpillar

Problem:

The flywheel/coupling guard arrangement can cause a low air pressure area at the front generator bearing. This low air pressure area can result in oil being pulled from the bearing seal. This oil is drawn into the cooling air stream for the generator and gets onto the windings of the generator.

Solution:

The coupling guard assembly can be modified to prevent the low air pressure area from developing by the front generator bearing.

Modification Procedure

A series holes can be drilled in the 4P-6974 and 6I-1944 Guard Assemblies. These holes will help prevent an air pressure differential between inside and outside the coupling guard group.

1. Remove the eight bolts and washers that fasten guard assembly (A) to guard (B). See the illustration. Remove the guards from the engine to facilitate drilling.

2. Three vertical rows of 1/4 or 3/8 inch holes should be drilled around each guard assembly as shown in the illustration. Maintain a 3 inch space on both sides of the joints between upper and lower guard assemblies. Assembly (A) can be rotated to get access to the lower coupling guard as required.

3. The centerline of the first row of new holes should be located 1/4 inch away from the edge of the guard assemblies nearest the generator. The holes in each row should be 1 inch away from each other. Subsequent vertical rows should be 1/4 inch from the preceding row. This creates a drilling area between 1-1/4 and 1-5/8 inches wide around the coupling guard assemblies. See the illustration.

4. After all the holes have been drilled, put guard assembly (A) in position on guard (B) and install the eight bolts and washers that fasten guard assembly (A) to guard (B).

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