2007/12/17 Caterpillar

Wheel Scraper:

621G (S/N: ANG1-UP; CEP1-UP; DBX1-453)

627G (S/N: AYK1-UP; CEZ1-UP; DBZ1-770)

631G (S/N: DEM1-304; CMT1-UP; AXZ1-UP)

637G (S/N: AWE1-UP; CEJ1-UP; CEM1-UP; AYN1-UP; DEX1-337; DEY1-213)

657G (S/N: W1E1-UP; W1F1-145; GER1-UP)

621E (S/N: 2TF1-UP; 6BB1-UP)

621F (S/N: 5JK1-UP; 9NL1-UP)

627E (S/N: 6FB1-UP; 6HB1-UP; 3WJ1-UP)

627F (S/N: 4YK1-UP)

631E (S/N: 1BB1-UP; 6PC1-UP; 4LD1-UP)

633ESeries II (S/N: 1EB1-UP)

637E (S/N: 1HB1-UP; 7CB1-UP; 1LB1-UP)

651E (S/N: 5XR1-UP; 88Z1-UP)

657E (S/N: 6MB1-UP; 6PR1-UP; 7KR1-UP; 86Z1-UP; 87Z1-UP)

ReferenceSpecial Instruction, REHS4210, "Procedure to Repair the Wheel Tractor-Scraper Plate Assemblies and Cylinder Support Assemblies"

Description of Change: The improved welding process for certain models of Wheel Tractor-Scrapers will repair cracks that can occur on top of the gooseneck. This process will extend the service life of the machine.

Adaptable To: The improvement to the Wheel Tractor-Scrapers' plate assemblies is effective with the following machines:

• 621E (S/N: 2TF1-UP; 6BB1-UP)

• 621F (S/N: 5JK1-UP; 9NL1-UP)

• 621G (S/N: ANG1-UP; CEP1-UP)

• 627E (S/N: 6FB1-UP; 6HB1-UP; 3WJ1-UP)

• 627F (S/N: 4YK1-UP)

• 627G (S/N: AYK1-UP; CEZ1-UP)

• 631E (S/N: 1BB1-UP; 4LD1-UP; 6PC1-UP)

• 631G (S/N: AXZ1-UP; CMT1-UP)

• 633E (S/N: 1EB1-UP)

• 637E (S/N: 1HB1-UP; 1LB1-UP; 7CB1-UP)

• 637G (S/N: AYN1-UP; AWE1-UP; CEJ1-UP; CEM1-UP; DEY1-213)

• 651E (S/N: 5XR1-UP; 88Z1-UP)

• 657E (S/N: 7KR1-UP; 6PR1-UP; 86Z1-UP; 87Z1-UP; 6MB1-UP)

• 657G (S/N: GER1-UP; W1E1-UP)

The improvement to the Wheel Tractor-Scrapers' brackets is currently installed on the following machines:

• 621G (S/N: DBX454-UP)

• 627G (S/N: DBZ771-UP)

• 631G (S/N: DEM305-UP)

• 637G (S/N: DEX338-UP)

• 657G (S/N: W1F146-UP)

The repair process will cover multiple sizes of machines. Refer to Table 1 for affected part numbers.

Table 1

Affected Parts
Machines	Part Number	Description
620	8X-7060	Plate As (LH)
620	8X-7059	Plate As (RH)
620	8J-7178	Cylinder Support Assembly
630	8X-7133	Plate (RH)
630	8X-7131	Plate As (LH)
650	8X-6952	Plate As (LH)
650	8X-6951	Plate As (RH)

The problem can be identified by a simple visual inspection. Refer to Special Instruction, REHS4210 for repair information.