KIT-SEAL 2558171 - Caterpillar

Locating and Repairing Cracks
1. Check for all visible cracks in three locations. Where the side plates join the rear casting at location (A), between the guide key housing and the main roller frame assembly at location (B), and at the visible weld between the rear casting and main tube at location (C).2. With an air carbon arc torch or similar tool, cut the cracks to their full depth. Weld the cracks with 4.0 mm (.156") Ø E7018 electrodes.3. If the cracks at location (B) extend into the main tube assembly, it will be necessary to remove the rear roller from the rear middle major bogie and bogie support pads. Cut an access opening in the bottom of the roller frame at location (D).4. After the opening has been cut, a visual inspection will determine if it is also necessary to cut an access opening below support rib (1). If the crack extends into the main tube assembly past rib (1), remove a section of the plate below support rib (1). Be careful not to damage the support rib or the main tube assembly.5. Check the weld in area (E), where the tube and casting meet, to make sure it is free of cracks.6. With an air carbon arc torch or similar tool, cut the cracks to their full depth. Weld the cracks with 4.0 mm (.156") Ø E7018 electrodes. When welding near the guide key housing, allow the weld to cool (to hand touch) before again applying weld. Too much heat will cause distortion.7. Install the sections of the bottom plate that were removed for access. If the sections were destroyed, new ones can be fabricated using a high strength structural steel with a minimum yield strength of 290 MPa (42,000 psi)
The bottom plate is a structural member of the roller frame, and it is important that any weld applied have 100 percent penetration.
8. If the crack extends into the main tube assembly, and due to location or access it is not practical to repair it from one side only, the crack can also be repaired from the inside of the tube assembly. Any weld applied to the inside diameter of the tube assembly must be ground flush to prevent interference with the front roller frame.9. Depending on the location of the crack, it is also permissible to remove a section of the side plate at location (F) to allow for easier access when repairing the crack from the outside.10. If the bogie pad mounting holes were affected during the rework, put the bogie pad in place and transfer the hole locations to the bottom plate of the roller frame. Drill four 11 mm (.42") Ø holes and make threads with a 1/2"-13 tap. Make sure the welds under the pad have been ground smooth, and the pad fits flat.Pressure Testing the Frame
1. Pressure test the frame to detect other cracks, after all visible cracks have been repaired. 2. Fabricate a fitting that will adapt an air pressure