ENGINE AR- 6I3657 - Caterpillar

Locate the crack. Cracks have been found on the bucket side, on the boom side, and on both sides.
Illustration 9 g06089071
Cross section of weld
Gouge the cracked area. Gouge a 45 degree V-groove opening the full length of the weld. Do not damage backing plate (5) when gouging.
Grind the gouged groove to clean and eliminate any traces of gouging contamination.
Perform a visual test and a penetrant test on the prepared groove. If the results still reveal signs of cracking or defects, continue gouging and grinding until the groove passes inspection.
Illustration 10 g06089118
Install a temporary steel support (7) at the edge of the groove and weld the groove.Note: Ceramic supports may be used as an alternative. Copper supports are forbidden due to the risk of contamination.Note: Lake of fusion is not allowed.
Reweld using multiple layer parameters while limiting structure temperature to a maximum of 200° C (392° F) 30 mm from the weld axis. Use a pneumatic needle scaler between each weld pass to reduce induced stress.
Repeat this process if another crack was found.
Illustration 11 g06089145
Cross section of weld
(8) Weld layers
(9) Repair weld
(10) Original weld
Add boom side and bucket side surface weld layers (8) to increase material section and thus increase stress flow distribution.
Illustration 12 g06089219
(A) Grinding direction
(B) Grinding marks
Illustration 13 g06089224
Cross section of weld
(C) Smooth section transition
(D) Minimum thickness
Illustration 14 g06089886
After grinding smooth
Remove the backings and clean up the backsides on the weld ends. Grind the weld surface to get a smoother section transition while maintaining a minimum thickness of 18 mm (for 390F) or 16 mm (for 390D). Finish the grinding with a flat grinding disk.No grinding marks over 0.5 mm are allowed. Large marks may stress the weld. Grinding must be done with the grinder moving in the same direction as the weld to have the grinding marks on the longitudinal side of the stick.
Perform a visual inspection on the repair. After, perform penetrant testing and ultrasonic testing to validate the repair. Use straight and angled beams during ultrasonic testing.
Paint the repair area using Caterpillar paint.
Install the stick as outlined in the applicable Disassembly