GEAR 8N3238 - Caterpillar

Dimensions for Fabricated Wheels
* The following charts and illustrations provide the important dimensions for inspecting the wheels during and following repair. All radius must be at a minimum of 0.5 mm (.02 in) and all edges must be deburred.
Illustration 16. 773/773B/773D OHT 8D-4934 and 2G-5003. When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face. This may require additional material or machining to correct dimension.
Illustration 17.777, 777B, 777C, 777D OHT 6G-6563 When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face.
Illustration 18. 777 OHT 6G-3658. When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face.
Illustration 19. 785, 785B OHT 8X-2633 and 5T-9539. When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face.
Illustration 20. 789, 789B OHT 8X-2636, 8W-9929 and 5T-5842. (3 pc) When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face.
Illustration 22. 789, 789B OHT 125-0061. (2 pc) When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face.
Illustration 21. 793, 793B OHT 8X-1019 and 102-0313 When welding is complete, measurement "D" must be checked to determine shrinkage of carrier face. Cast Wheel Weld Procedure
It is NOT recommended to proceed with cast wheel repair procedure if cracks appear in bearing bores or splines.
Repairs must be made to the wheel with a soaking preheat and interpass temperature of 150 °C (300 °F) and not exceeding 204 °C (400 °F) shall be maintained 76.2 (3 in) on either side of the weld repair or wrapper band area.
1. Attach welding ground cable directly to wheel assembly. Do NOT allow welding current to travel through the machine's bearings or hydraulic cylinders. Protect all hydraulic cylinders, struts, hoses and machined surfaces from sparks or spatter produced by the welding, chipping and grinding operations.2. Locate and remove any cracks with carbon arc gouging method or grinding. Gouge or grind completely to the bottom of crack and a minimum of 18 mm (.708 in) past each end of the crack. Use a rotary file to "dress" the area and remove carbon or any rough edges. Remove all slag, spatter and clean repair joint. Use adequate light and magnetic particle or magnuflux inspection to verify any cracks have been completely removed. An alternate method of crack removal is machining. Machine off only enough material to assure total crack removal and weld joint repair integrity.3. Weld repair joint using stringer beads or weave as desired. Slag each pass to avoid possible slag inclusions. Welding pass size should be manageable and generally not exceed two times the electrode diameter. Single pass of 3.17 mm (.125 in) E7018, weld metal should be two times the electrode diameter. If the alternate welding process is selected, the welding pass size should NOT exceed 7.874 mm (.31 in) fillet volume.4. Allow the wheel assembly to slowly cool to room temperature and check wheel assembly dimensions. All dimensions must be within tolerance prior