TAP-TAPER 4C5011 - Caterpillar

Rework Procedure
Illustration 1 g06179446
View showing the location of bevel weld joint on the right-hand frame rail (parts removed for clarity)
(A) 90.04 mm (3.54 inch)
(B) Transmission mountIf cracks are detected on either frame rail at this location, complete this rework procedure for both right-hand (RH) and left-hand (LH) frame rails.
Using dimension (A), find the location of the bevel weld joint, rearward the edge of transmission mount (B), on the frame rail. Inspect for weld seam cracks.Note: Weld seam cracks may appear on RH rail assembly or LH rail assembly of the rear frame. In certain heavy-duty applications weld seam cracks may appear on both sides of the rear frame.
Illustration 2 g06179464
View showing example of crack on the outside plate of right-hand frame rail
(C) 25 mm (0.98 inch)
(D) 27 mm (1.06 inch)
Identify the length of the crack on the side plates of the frame rails.
Use the following weld process to repair upper rail plate cracks within 25 mm (0.98 inch), dimension (C), on the side plates.
Illustration 3 g06179474
View showing scarfing dimensions
(E) 60 degrees
(F) 90 degrees
Illustration 4 g06179475
View showing weld joint after scarfing
Scarf down into the joint until you can see the lower edge of the forward bar depth of about 25 mm (0.98 inch).
Ensure that the crack and any weld defects are removed.
Open up bevel to between 60 degrees (E) and 90 degrees (F) as shown in Illustrations 3and 4.
Completely remove all slag from the area.
Illustration 5 g06179477
View showing placement of run-off tab
(G) Run-off tab
Add temporary plates to each side of the rail in a “V pattern” to create a run-off tab (G). Extend run-off tab (G) past the edges of the rail lengthwise as shown in Illustration 5.Note: Run-off tabs allow for starts and stops for each pass to be beyond the edges of the rail. Extended starts and stops will minimize weld defects.
Illustration 6 g06180351
View showing example of a finish welded seam joint
Weld the seam joint. After initial weld passes, inspect the weld for cracks. Grind the surface smooth to remove carbon. Add more weld passes until the "V" groove is filled. Finish with a cap pass that is high enough to grind off to make flush with the top surface, as shown in Illustration 6.Reference: Reuse and Salvage Guidelines, "Caterpillar Service Welding Guide", SEBD0512Reference: Special Instruction, "General Welding Procedures", REHS1841
Remove tabs (G) and grind the top and side surfaces smooth to the original rail profile.
Preferably perform a UT inspection to ensure adequate fusion and that the weld is free of defects.
Use the following weld process to repair side plate cracks within 27 mm (1.06 inch), dimension (D). Refer to Illustration 2.
Grind the crack 1/4" to defect side. Ramp at both ends and sides.
Weld the area using ‘direct’ feed at root.Reference: Reuse and Salvage Guidelines, "Caterpillar Service Welding Guide", SEBD0512Reference: Special Instruction, "General Welding Procedures", REHS1841
Use the following weld process to repair side plate cracks beyond 27 mm (1.06 inch), dimension (D). Refer to Illustration 2.
Grind the crack 1/4" to defect side. Ramp at both ends and sides.
Fabricate a back-up strip.
Use a 1/8" thick