HARNESS AS-SWITCH 4373082 - Caterpillar

Introduction
A new bushing is available for the grapple head through the Caterpillar parts department. The process that is described below provides the needed information in order to install a new 224-4979 Bushing in a grapple head.Do not perform any procedure that is outlined in this Special Instruction until you have read the document completely and you understand the information that is contained in the document.Safety
Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc.Welding can cause fumes, burn skin and produce ultraviolet rays.Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working.Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death.Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts.See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society.American Welding Society
2501 N.W. 7th Street
Miami, Florida 33125
See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor.U.S. Department of Labor
Washington, D.C. 20210
Procedure to Install the New Bushing
Illustration 1 g01157443
(1) 224-4979 Bushing
Freeze the new bushing to -68 °C (-90 °F) for at least one hour in order to shrink the bushing and ease installation. Handle the frozen bushing with the appropriate equipment. Use a 1P-0520 Driver Gp in order to install the bushing. Install the bushing in the bushing bore so that the bushing is flush with both sides of the lug on the grapple head. Note: Make sure that the splined side of the bushing is installed with the splines toward the center of the grapple head. The smooth bore side of the bushing will face the outside of the grapple head.
Use a torch in order to gently heat the bushing to 32 °C (90 °F).
Position the grapple head so that the bushing bore faces upward. Cover the bore of the bushing with a metal disc. The metal disc should be larger than the inside diameter of the bushing. This will prevent welding spatter from getting on the splines of the bushing and the smooth bore of the bushing.
Fillet weld the J-groove between the bushing and the lug. Use one root pass and one final pass for the weld. Make sure that the weld does not contact the metal disc that is covering the bushing. The following welding processes are preferred for this repair.
Table 1
Gas Metal Arc Welding (GMAW)    
Use 35 5 CFH of 75% Argon and 25% CO2.    
Mixed Shielding Gas    
"AWS Class ER70S-3"    
Table 2
Flux Cored Arc Welding (FCAW)    
"AWS Class E71T-1"    
Use the manufacture's suggestion for the gas mixture and the flow.    The following welding process is acceptable for this repair.
Table 3
Shielded Metal Arc Welding (SMAW)