Rework Procedure for the Boom Nose on Certain 313D2 LGP Excavators {6501} Caterpillar

Introduction

This Special Instruction is intended to provide a rework procedure for the boom nose on 313D2 LGP.

Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.

Safety Section

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Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted. When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support. The swing lock (if equipped) must be engaged before service is started. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

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Personal injury can result from flame cutting or welding on painted areas. The effect of gasses from burned paint is a hazard to the person doing the cutting or welding. Do not flame cut or weld on painted areas.

Required Parts

Welding on Machines and Engines with Electronic Controls

Proper welding procedures are necessary to avoid damage to the electronic controls and to the bearings. The following steps should be followed to weld on a machine or an engine with electronic controls.

1. Turn off the engine. Place the engine start switch in the OFF position.

2. If equipped, turn the battery disconnect switch to the OFF position. If there is no battery disconnect switch, remove the negative battery cable at the battery.
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   NOTICE
   Do NOT use electrical components (ECM or sensors) or electronic component grounding points for grounding the welder.

3. Connect the welding ground cable to the boom.

4. Clamp the ground cable from the welder to the component that will be welded. Place the clamp as close as possible to the weld. Make sure that the electrical path from the ground cable to the component does not go through any bearing. Use this procedure to reduce the possibility of damage to the following: bearings of the drive train, hydraulic components, and electrical components and other components of the machine

5. Protect any wiring harnesses from the debris which is created from welding. Protect any wiring harnesses from the splatter which is created from welding.

6. Use standard welding procedures to weld the materials together.

Welding Requirements

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Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc. Welding can cause fumes, burn skin and produce ultraviolet rays. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working. Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can cause death. Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts. See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society. American Welding Society 2501 N.W. 7th Street Miami, Florida 33125 See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor. U.S. Department of Labor Washington, D.C. 20210

Welding quality is critical to the success of the installation procedure. Welds must be smooth and continuous. Undercutting and/or overlapping is allowed. Grind the ends of the welds to a smooth radius.

Prepare the metal for welding. Refer to the illustrations in this special instruction for welding symbols and specifications.

Use LB-26 Electrodes (AWS E7016 or AWS E7018) or equivalent electrodes to weld the baffle plate and the reinforcement plates. Basic welding wire ESAB OK tubrod 15.00 with a 1.2 mm (0.05 inch) diameter can also be used. The basic welding wire must be the equivalent to AWS E70S with positive polarity. The welding wire must be shielded with CO₂ gas.

Welding of the V-groove requires LB-52 (AWS E7018), or an equivalent electrode. Basic welding wire ESAB OK tubrod 15.00 with a 1.2 mm (0.05 inch) diameter can also be used.

Dry all electrodes before use. The electrodes can be dried by heating the electrodes to 300°C (572°F). The electrodes must be dried for at least 30 minutes.

Do not weld in windy conditions. Do not weld when temperatures are below 16°C (60°F).

Penetration characteristics may vary greatly depending on the electrode diameter, shielding gas, welding current, and plate thickness. Geometry of welded joints, surface conditions, and composition of the base metal and electrode also affect the welds.

A root pass should be applied before each weld is finished.

Maintain a 3 mm (0.12 inch) minimum root opening on all cross welds and circle welds.

All the welds to the boom must be in the direction from the rear of the boom toward the front of the boom, unless the directions of the welds are otherwise specified.

For more information, consult the AVSpare Service Welding Guide, SEBD0512.

Rework Procedure

The cracks on the boom nose bracket initiated along the weld seam between the side plate and the v section. Repair the boom nose crack referring to the following rework procedure.

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Illustration 1	g06021441
Crack stayed at the weld area (dotted line represents the crack)

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Illustration 2	g06021739
Crack reached the base metal (dotted line represents the crack)

1. Check the condition of the boom nose crack. If the crack has stayed in the weld seam area, proceed to the next step. If the crack has reached the base metal, replace the entire bracket assembly on the boom nose with a new 477-9380 Bracket As. Refer to Special Instruction, SEHS0068 , "Procedure to Replace the Bracket Assembly of the Boom Nose on Reach Booms for Certain D Series, E Series, and F Series Excavators"
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   Illustration 3	g06022079
   (1) Crack (2) Weld (3) Base metal

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   Illustration 4	g06022085
   (4) Remove the crack and weld

2. Remove the crack and weld by gouging or grinding.
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   Illustration 5	g06022098
   (5) Fillet 12mm with 1.5mm penetration

3. Apply fillet 12 mm (0.47 inch) with 1.5 mm (0.059 inch) penetration weld and add grinding for the weld and near area surfaces.