PIN 5C7107 - Caterpillar

Introduction
This Special Instruction provides the necessary parts and information required to repair cracks in the upper plate of the boom.Reference: Service Manual, Parts Manual and Caterpillar Service Welding Guide, form SEBD0512.Welding Requirements
Weld quality is critical to the success of this installation. Welds should be as smooth and continuous as possible.All electrodes must be completely dry. Dry electrodes at 300°C (572.0°F) for a minimum of one-half hour.Do not weld in areas where there is air movement or in temperatures below 15.5°C (60°F).Use AWS E7016 electrodes or their equivalent.Cleaning Procedure
All foreign material such as grease, water, paint, rust, dirt and scale must be removed before welding. These materials discharge gas when they come into contact with heat. This gas can cause porosity (very small bubbles) in the weld deposit. Water or rust can cause a condition known as "hydrogen embrittlement", resulting in cracks in the weld deposit.Remove all oil and grease with solvent. Remove paint, rust, dirt and scale with a brush or by blasting with glass beads.Cracks
No cracks are permissible, external or internal. If external cracks are suspected, the part should be thoroughly cleaned and Magnafluxed.X-Ray or Ultrasonic methods are ideal to check for internal cracks. However, these methods are more involved and require a special shop to perform the checks.If the cracks are repairable, they should be cut or ground out approximately 6 mm (.25 in) deeper than the original crack when possible. Fill the hole with weld.To ensure a good weld, the material around the weld are should be heated to 230 28°C (450 82°F) during the welding process on the part being repaired.Parts Needed
Fabrication
Reinforcing Plate Reinforcing plate dimensions are before bending.Fabricate one reinforcing plate (C) using 1E1883, ASTM A36 or equivalent 16 mm (.63 in) thick steel.
Reinforcement Plate (D)Fabricate two reinforcement plates (D) using the chart below. Use ASTM A36 or equivalent 16 mm (.63 in) thick steel.
BlockFabricate one block (H) using 1E1883, ASTM A36 or equivalent 32 mm (1.26 in) thick steel.Procedure
Location Of Cracks On Boom Upper Plate (Z) Cracks.1. Use a dye penetrant crack detection process to check for possible cracks.
Installation Of Block And Reinforcing Plates
(C) Reinforcing plate. (D) Reinforcing plate. (H) Block. (I) Harness clamps. (J) Support. (S) Stick cylinder bracket. (U) Location distance [1090.0 mm (42.91 in) measured on upper plate surface]. (V) Location distance [1000.0 mm (39.37 in) measured on upper plate surface]. (Y) Welds [to join existing weld].2. Grind out all cracks thoroughly. Remove existing block, three harness clamps and two supports from the boom upper plate.3. Use a torch and wire brush to thoroughly remove all moisture, oil and paint film from the immediate and adjacent ground areas.4. Weld the ground out portions. Use AWS E7016 electrodes.5. Grind the weld area smooth.6. Tack weld two reinforcing plates (D) to the boom side plates. Also tack weld one reinforcing plate (C) to the boom upper plate. Keep a clearance of 1 mm (.04 in) or less between plate (D) and boom side plates. Keep a clearance of 2