BUSHING 3F7445 - Caterpillar

Coupling Maintenance
Maintenance for the Rubber Flexible Coupling consists of four activities:
Keep the coupling free of excessive heat, UV light, petroleum products, solvents, anaerobic adhesives, and ozone.
Periodically inspect the rubber and the metal components for any imperfections, for stress, and for wear.
Check the torque for the fasteners periodically.
Check the alignment periodically.
Illustration 1 g01323258
(1) Rubber areas that are peeling away from the steel hub (2) Wear at the loaded side of the teeth
Illustration 2 g01323319
Detail ACracks in the rubberDuring visual inspection of the rubber element, note any rubber areas that are peeling away from the steel hub. A wear of 3 to 4 mm (0.118 to 0.157 inch) at the loaded side of the teeth is allowable. Refer to Illustration 1.During visual inspection of the rubber element, note any tears or cracks in the center of the rubber element. Refer to Illustration 2.Inspection
Torsional Set
Illustration 3 g01323355
Torsional set of rubber coupling (X) Distance of torsional set (Y) Diameter of molded edgeUse the following steps to determine the amount of torsional set of a rubber coupling. Refer to Illustration 3.
Use a straight edge and the centerlines of the holes on the inner hub. Put a mark on the edge of the mold line of the rubber element.
Use a straight edge and the centerline of a tooth space. Put a mark on the edge of the mold line that is on the rubber element.
Measure the distance between the marks. Replace an element when the torsional set (X) exceeds 25 mm (1 inch).Cracks
Examine all rubber surfaces for cracks. Refer to Illustration 2.Length - Acceptable hairline cracks are random and short. Cracks that radiate diagonally from the center of the rubber element indicate that the rubber element has failed. The rubber element must be replaced. Depth - The rubber element must be replaced if there are cracks that exceed 3 mm (0.12 inch).Width - Walls that are clearly visible from the bottom of crack indicate that the rubber is seriously hardened or the rubber is damaged. Replace the rubber element.Tooth Wear
3 to 4 mm (0.12 to 0.16 inch) of wear on the loaded edge of the tooth on the rubber element is allowable. A gap of a few millimeters between the rubber and the drive ring is normal. Centrifugal force stretches the rubber element in order to contact the drive ring in normal operation.Bond Lines
A bond line is the joint between the metal hub and the rubber element. Examine this area for separation. If separation that is not clearly an air space from the manufacturing process is present, the rubber element must be replaced.Bulges or Swelling
Any bulge or any swell that is larger than 6 cm2 (2.4 inch2) requires replacement of the rubber element.Rubber Hardness
Use a durometer. Use the Shore A hardness scale. Check the rubber hardness in several locations. The rubber hardness must be the following value.Original shore hardness ... 3