A Mainframe Rework Procedure is Now Available on Certain Pipelayer {7051} Caterpillar

Pipelayer

PL87 (S/N: KKJ1-UP)

Introduction

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

This special instruction provides the procedure to repair cracks around the Pipelayer tower support for the Pipelayer crossbeam structure on the machine mainframe. This procedure is applicable for cracks that are less than 300 mm (11.81 inch) long.

For cracks exceeding this dimension, report the failure through the CPI feedback tool in Service Information Management System (SIMSi) referencing CPI number 406974 for more instructions. This procedure requires welds to be ground and installation of reinforcement material.

Safety Section

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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility.

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Failure to follow all safety guidelines prescribed in this document and by governing authorities and regulatory agencies may result in severe injury or death of personnel or machine damage.

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When removing a major component or attachment, ensure that it is properly blocked or secured before removing mounting hardware. An assembly that is disconnected without proper blocking may shift or fall, resulting in serious injury or death of personnel or machine damage.

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Climbing equipment may be required to access this service point. Refer to the Operation and Maintenance Manual, "Mounting and Dismounting" topic for safety information.

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Before servicing/performing maintenance on the machine, electrical power must be physically disconnected; battery plugs must be disconnected from the batteries, or the trailing cable must be unplugged, and warning tags and padlocks shall be applied by a certified electrician. Certified electricians shall perform or direct any electrical work, including any energized testing, repair work in controllers, motors, or other approved compartments, and shall insure that all compartments are properly closed and inspected prior to re-energization. All applicable lock out and tag out procedures must be followed.

Reference Section

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

Reference: Reuse And Salvage Guidelines, SEBD0512, "Service Welding Guide"

Reference: Operation and Maintenance Manual, SEBU8007, "PL87 Pipelayer"

Reference: Disassembly and Assembly, UENR1325, "PL87 Pipelayer Machine System"

Processes for Repair and Welding

Use the following electrodes: low hydrogen E7018 electrode, E70S-3 (dual shield) solid wire, and E71T-1 flux cored wire.

All electrodes must be dry.

Do not weld in areas if there is a strong movement of air or in temperatures of less than 16 deg C (61 deg F).

The following welding processes are acceptable for this procedure:

• Gas metal arc welding (GMAW) - Use 35 ± 5 cfh of shielding gas (75% argon and 25% carbon dioxide).

• Flux cored arc welding (FCAW) - Use 35 ± 5 cfh of shielding gas (75% argon and 25% carbon dioxide). The FCAW process is called the AWS Class E71T-1 process.

• Shielded metal arc welding (SMAW) - Use E7018 electrodes in this DCEP process.

• Air arc gouging (DCEP) - Use 5/16 inch diameter rods for carbon arc.

Rework Preparation

• Tracks need separated to provide access to the inside mainframe area.

• Remove extra hardware as needed for access.

• Securely cover all hose and engine components to protect from welding, carbon arcing, and grinding.

Required Parts

All fabricated plates are 290Mpa yield strength.

ASTM A572 Grade 42 or 50.

EN10025 s355k2g3 or equivalent.

Illustration 1	g06313352
(Plate 1) 10 mm (0.39 inch) thick

Illustration 2	g06313362
(Plate 2) 10 mm (0.39 inch) thick

Illustration 3	g06313659
(Plate 3) 10 mm (0.39 inch) thick

Rework Procedure

Right-hand Tower

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Illustration 4	g06313675
(D1) 100 mm (3.94 inch)

1. Cut tower plate (A) along the outside edge. See Illustration 4 for dimension (D1) of cut.

   Note: Cracks in side sheet less than 300 mm (11.81 inch) should be ground or cut out, and then rewelded and ground flush.

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   Illustration 5	g06313683
   (W1) 12 mm (0.47 inch)

2. Reweld all welds (W1) that were cut out.
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   Illustration 6	g06313687

3. Locate plate (1) against the fillet weld and tack into position. Top edge should be in line with tower plate (A).
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   Illustration 7	g06313689
   (D2) 90 mm (3.54 inch) (W2) 8 mm (0.32 inch)

4. Weld (W2) all the way around plate (1). Terminate weld (W2) at dimension (D2).

5. Weld the gap between plate (1) and plate (A).

Left-hand Tower

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Illustration 8	g06313691
(D3) 150 mm (5.90 inch)

1. Carbon Arc out weld and plate (B) tips. See Illustration 8 for dimension (D3).

2. Discard excess plate (B) tips.
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   Illustration 9	g06313697

3. All cracks should be ground out and reweld. Grind plate (B) flush.
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   Illustration 10	g06313702
   (W1) 12 mm (0.47 inch)

4. Weld (W1) cut edges of plate (B).
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   Illustration 11	g06313703

5. Locate plates (2) at the top edge of plate (B). Tack plate (2) into position.

6. Center plate (3) with respect to tower (C).
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   Illustration 12	g06313704
   (D3) 150 mm (5.90 inch) (W2) 8 mm (0.32 inch)

7. Weld (W2) all the way around two plates (2). Terminate weld (W2) at dimension (D3).

8. Weld (W2) all the way around plate (3).

   Note: If access prevents from welding all the way around plate (3), see the weld in Illustration 12.

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   Illustration 13	g06313705

9. Weld the gap between plates (2) and plate (B). Weld the gap between plate (3) and plate (B).