CONTROL AS-ELECTRONIC 3560029 - Caterpillar

applicationsReference: "New Main Shaft Bearing Assembly Has Reduced End Clearance" in the March 25, 1985 Service Magazine.When measuring end clearance of a tapered bearing, be sure not only to put force on the shaft, but also to rotate the shaft before reading the dial indicator. This forces the rollers to move up the cone and make contact with the cone rib. If the bearing is not rotated, the reading will be less than the actual end clearance.
The shaft should be rotated at the same time the force is applied to the end of the shaft.
The force needed depends on bearing size. About 890 N(200 lb) is required, for example, on the 7251 and 7261 Marine Transmissions.
Use the following general procedure to measure end clearance in all tapered bearings.
1. Mount a dial indicator in a convenient place so the indicator indicates fore and aft movement of the shaft.2. Put a force on the shaft in one direction with a pry bar and zero the dial indicator at zero.3. Mark the exact location on the shaft where the dial indicator stylus touches.4. Force the shaft in the opposite direction and again rotate it to seat the rollers. Read the end play with the dial indicator stylus in the position marked earlier.5. Repeat the procedure until the same reading occurs twice.