Caterpillar SR4B: Maintenance Interval Schedule (Standby) (Overhaul)

The following maintenance procedure for generator bearings should be followed at every major engine overhaul:

• Remove the bearing bracket. Inspect the following items: bracket bore, bearing outer race, and rolling elements. On Standby Power Units, the bearing must be inspected and the grease must be replaced at three year intervals. The bearing bracket sleeve should be inspected for out of roundness, excessive wear, and a bracket step that is less than 0.0762 mm (0.0030 inch). If there is no bearing bracket sleeve, inspect the bearing bracket bore. The bearing should be inspected for outer race damage, severe fretting, and smoothness of operation. When possible, the bearing elements should be inspected. Some double shielded ball bearings prevent visual inspection of the ball bearing elements. Other double shielded ball bearings have a retaining ring. This retaining ring can be removed in order to allow access for a visual inspection of the ball bearing elements.

• Spherical Roller should be cleaned and repacked with 108-8611 Grease. Pack the bearing and pack the cavity (one-third to one-half of the cavity volume). The bearing should be filled with 88.8 ml (3 ounces) to 118.4 ml (4 ounces) of grease. The cavity should be filled with 118.4 ml (4 ounces) to 148.0 ml (5 ounces) of grease.

• All ball bearings should be cleaned.

• Ensure that the grease supply tube to the bearing is filled with grease.

• Remove the bracket drain plug and operate the generator for one hour. This will allow the grease to expand. The expanding grease will force the excess grease from the cavity. When the excess grease is forced from the cavity, the internal pressure will be reduced. The generator should continue to operate until the grease stops purging.

• Stop the engine. Install the bracket drain plug. Wipe off the excess grease.