Procedure to Install New Plates on the Rear Frame on Certain 651E, 657E, and 657G Wheel Tractor-Scrapers{7050, 7051} Caterpillar

Wheel Tractor-Scraper:

651E (S/N: 4YR1-UP)

657E (S/N: 5YR1-UP; 6TR1-UP)

657G (S/N: W1B1-UP; W1C1-UP; A4G1-UP)

Introduction

The following procedure is an instruction for the installation of plates onto the rear frame of the Wheel Tractor-Scrapers that are listed above. The new plates will prevent mud and other debris from collecting inside the rear frame of the machines. Refer to the references below for general welding procedures.

ReferenceSpecial Instructions, REHS1841, "General Welding Procedures"

Safety Section

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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.

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Caterpillar dealer for replacement manuals. Proper care is your responsibility.

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Personal injury or death can result from improper troubleshooting and repair procedures. The following troubleshooting and repair procedures should only be performed by qualified personnel familiar with this equipment.

Required Materials

Welding Details

ReferenceRefer to Special Instructions, REHS1841, "General Welding Procedures" for additional welding instructions.

Shielded Metal Arc Welding

The Shielded Metal Arc Welding (SMAW) process may be used with the E7018 (ANSI/AWS A5.1) welding electrode. The weld that will be deposited by these electrodes will have the following mechanical properties.

These low hydrogen electrodes must be stored in an electrode oven at 120 °C (248 °F) when the electrodes are not being used. Scrap the electrodes if the electrodes get damp.

Note: Welding parameters will vary due to the position of the weld and the parameters will vary due to the manufacturer of the welding electrode.

The following chart relates to the electrode diameter and approximate current settings for welding.

The welder should be set to use the DC reverse polarity setting. Remove all slag after every pass. Weld all joints from the bottom upward. The number of weld passes will depend on the width of the weld joint. Remove all slag after welding. Inspect the weld for low areas. Grind high spots in the weld with a coarse pad. Be sure not to grind out any base material. Finish blending the weld with a fine pad. No sharp edges are acceptable.

Flux Cored Arc Welding

The Flux Cored Arc Welding (FCAW) process may be used with the E71T-1 (AWS A5.20) welding electrode. The FCAW process may also be used with shielding gas. The weld that will be deposited by these electrodes will have the following mechanical properties.

Note: Welding parameters will vary due to the position of the weld and the parameters will vary due to the manufacturer of the welding electrode.

For a 1.1 mm (0.045 inch) electrode, the typical welding parameters should be the following.

For a 1.3 mm (0.052 inch) electrode, the typical welding parameters should be the following.

The welder should be set to use the DC reverse polarity setting. Remove all slag after every pass. Weld all joints from the bottom upward. The number of weld passes will depend on the width of the weld joint. Remove all slag after welding. Inspect the weld for low areas. Grind high spots in the weld with a coarse pad. Be sure not to grind out any base material. Finish blending the weld with a fine pad. No sharp edges are acceptable.

Note: All vertical welds will be welded with a vertical up technique.

Machine Preparation

1. Completely clean the underside of the rear frame. The frame should be clear of all mud, sediment, and grease.

2. Use a grinder in order to remove all paint from the area around the opening in the rear frame. All future surfaces for welds must be clean of paint, sediment, and grease.

Installation of the New Plates

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Illustration 1	g02023124
(A) 315.8 ± 1 mm (12.43 ± 0.04 inch) (B) 74.6 ± 1 mm (2.93 ± 0.04 inch) (C) 112.8 ± 2 mm (4.44 ± 0.08 inch) (D) 108.8 mm (4.28 inch) (E) 74.6 mm (2.94 inch) (F) 217.5 mm (8.56 inch) (G) 420 mm (16.54 inch) (H) 108.8 mm (4.28 inch)

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Illustration 2	g02023276
Distance from the bottom of the bracket assembly (3) to the top of the rear frame (7) is 46 mm (1.8 inch). (3) Bracket assembly (6) Plate assembly (7) Top of the rear frame

Note: Refer to Table 7 in ""Welding Details" " for welding specifications for this instruction.

1. Refer to Illustration 1 and refer to Illustration 2 in order to locate the new bracket assembly (3), bracket assembly (4), and plate assembly (6) .

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Illustration 3	g02023292
View of the new cover assembly (2) in position

2. Tack weld all of the new plates into position.

   Install the new cover assembly (2) in order to verify the correct fit. Use eight bolts (5) and use eight hard washers (1) in order to install the new cover assembly.

3. Remove the cover assembly (2) .

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Illustration 4	g02023410

4. Weld (W2) and (W3). Refer to Illustration 4. The welds should be continuous. Tie all welds at the corners.

   Note: The distance between Welds (W2) and (W3) is 56 mm (2.2 inch).

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Illustration 5	g02066453

5. Weld (W1). Refer to Illustration 5. The weld should be continuous. Tie all welds at the corners.

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Illustration 6	g02023462

6. Weld (W1). Refer to Illustration 6. The weld should be continuous. Tie all welds at the corners.

7. Perform the exact welds that are described in Steps 4 through Step 6 to the two remaining plates.

Installation of the Hooks

1. Refer to Illustration 1 in ""Installation of the New Plates" " for the correct location of the new plate assembly (6) .

2. Tack weld the new plate assembly (6) into position.

3. Reinstall the new cover assembly (2) again in order to ensure correct placement of the new plate assembly (6). After correct placement is verified, remove the cover assembly (2) .

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Illustration 7	g02023836
View of the new plate assembly (6)

4. Weld (W4). Refer to Illustration 7. The weld should be continuous. Tie all welds at the corners.

5. Perform the same welds in 4 to the second hook.

6. Clean all welds and inspect all welds. Be sure that all welds are free of cracks and be sure that all corners are properly tied together. Any sharp edges on the weld joints must be cleaned up.

7. Apply paint to all weld areas. Apply paint to the new plates.

8. Install the new cover assembly (2) .