HOSE AS 3844299 - Caterpillar

All grease, paint, and foreign objects must be removed before welding. Any of these materials will discharge gas which will cause porosity in the weld deposit. Water and rust will cause hydrogen embrittlement. Hydrogen embrittlement causes cracks in the weld deposit.Remove foreign objects with a wire brush, a buffer, or a grinder. Shot blasting the appropriate areas will also remove foreign material.Note: After welding, allow all areas to cool to room temperature. After the areas have cooled, paint the area with primer. After the primer has dried, coat the area with Cat 4C-4200 Yellow Paint.Safety Section
Personal injury or death can result from sudden work tool movement.Sudden movement of the work tool can cause injury to persons near the work tool.To prevent injury or death, make sure that the area around the work tool is clear of personnel and obstructions before operating the work tool.
Required Parts
Table 1
Bracket Assembly
Model Part Number
311 - 319 378-2347 Bracket As
320 - 329 378-2486 Bracket As
330 - 336 378-2433 Bracket As
345 - 349 378-2467 Bracket As Installation Procedure
Prevent the machine from movement. Park the machine on a level surface.Attach a "Do Not Operate" warning tag to the start switch or controls before you service or repair the equipment. These warning tags (Special Instruction, SEHS7332) are available from your Cat dealer.This procedure will require the use of a suitable lifting device or devices to position the parts safely.
Illustration 1 g02692898
Machine Position
(A) Remove paint as necessary
Position the machine stick by fully extending the stick cylinder as shown.
Remove paint as needed for a clean welding surface in (A) as shown.
Illustration 2 g02697378
Bottom view of stick
(B) Center of pin bore to end of bracket
(D) Bracket (centered on stick)
(W1) AWS A5.18 ER70S-2 or equivalent
Illustration 3 g03336666
View of stick with a bracket that is wider than the stick
(G) WeldNote: When installing a stiff link thumb with a bracket that is wider than the stick, the bracket must be welded on the backside and along the stick base plate. Refer to Illustration
Center base plate (D) on the stick. Refer to Table 2 for dimension (B) from the center of pin bore to end of bracket and Illustration 2.
Table 2
Model Bracket Dimension (B)
311 - 319 378-2347(1) 150 2 mm (5.91 0.08 inch)
320 - 329 378-2486
330 - 336 378-2433
345 - 349 378-2467 250 2 mm (9.84 0.08 inch)
(1) Bracket is wider than the stick.Note: Do not weld across the ends of bracket (D).
Tack weld bracket (D) on the stick.
Weld the bracket to the stick. Refer to Illustration 2.Make a continuous weld from point (E) to point (F) on each end of the bracket.Weld each side of the bracket.
Allow the welded area to cool.
Prepare the welded area for paint.
Apply a rust prevention coat and a finish coat.Modification for Installation of Thumb on Heavy Duty Stick
Illustration 4 g03371886
View of heavy-duty stick
(A) Plate
(B) End of plate
(C) End of bracket
(D) Weld point
(E) Weld pointTo ensure a flat surface for welding the bracket to the stick, an additional plate may need to be