Installation Procedure for the 373-5844 Thumb Gp {0679, 6547, 7562} Caterpillar

Excavator:

315D (S/N: BYK1-UP; BZN1-UP; CJN1-UP; JGS1-UP)

Introduction

This special instruction covers the installation procedure for 373-5844 Thumb Gp .

Parts

Illustration 1	g02450539

Illustration 2	g02450716

Reference

• Reference Service Guide, SEBD0512, "Caterpillar Service Welding Guide"

• Reference Special Instruction, REHS1841, "General Welding Procedures"

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 procedures. Welds must be smooth and continuous. Do not undercut the welds. No overlap is allowed. Grind the ends of the welds to a smooth radius.

Prepare the metal for welding. Refer to ""Preparing the Metal for Welding" ". Refer to the illustrations in this Special Instruction for welding symbols and specifications.

Use AWS E7018 electrodes or equivalent electrodes to weld the guards to the work tool.

All electrodes must be dried completely. 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 following conditions:

• Electrode diameter

• Shielding gas

• Welding current

• Plate thickness

The following items also affect the welds:

• Geometry of welded joints

• Surface conditions

• Composition of the base metal and of the electrode

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 welds to the stick must be welded in the direction from the rear of the stick toward the front of the stick.

For more welding information, consult the Caterpillar Service Welding Guide, SEBD0512.

Preparing the Metal for Welding

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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.

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.

Remove any oil or grease with a Caterpillar approved solvent.

Welding on Machines and Engines with Electronic Controls

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

Note: If you are welding on a work tool, Caterpillar recommends removing the work tool from the host machine before welding.

1. Turn off the engine.

2. Turn the Battery Disconnect Switch to the OFF position. If there is no Battery Disconnect Switch, then remove the negative battery cable at the battery.

3. 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 in order to reduce the possibility of damage to the following components:

• Bearings of the drive train

• Hydraulic components

• Electrical components

• Other components of the machine

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

Installation

Illustration 3	g00104545

Prevent the machine from movement. Park the machine on a level surface.

Attach a "Do Not Operate" warning tag or a similar warning tag to the start switch or to the controls before you service the equipment. These warning tags (Special Instruction, SEHS7332) are available from your Caterpillar dealer.

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Illustration 4	g02450816
(A) 1652.5 mm (65.06 inch) (B) 45.4 mm (1.79 inch) (W1) 8 mm (0.32 inch) Fillet Weld all around (6) 262-7327 Bracket

1. Orient the stick of the host machine into a position suitable for welding the bracket (6) .

2. Locate the correct position for bracket (6) .

3. Weld the bracket in place.

4. Paint the welds.

5. Install the thumb (9) .

6. Install the hydraulic cylinder (8) .