Procedure for Salvaging Off-Highway Truck Wheel Bolt Holes or Stud Holes{4201} Caterpillar

Off-Highway Truck/Tractor:

768B (PIN: 79S1-UP)

768C (PIN: 02X1-UP)

769B (PIN: 99F1-UP)

769C (PIN: 01X1-UP)

769D (PIN: 5TR1-UP; 5SS1-UP)

772 (PIN: 11S1-UP)

772B (PIN: 64W1-UP)

773 (PIN: 63G1-UP)

773B (PIN: 7CS1-UP; 63W1-UP)

773D (PIN: 7ER1-UP)

775B (PIN: 7XJ1-UP)

775D (PIN: 6KR1-UP; 8AS1-UP)

776 (PIN: 14H1-UP)

776B (PIN: 6JC1-UP)

776C (PIN: 2TK1-UP)

776D (PIN: 5ER1-UP)

777 (PIN: 84A1-UP)

777B (PIN: 4YC1-UP)

777C (PIN: 4XJ1-UP)

777D (PIN: AGC1-UP; 3PR1-UP)

777D HAA (PIN: 2YW1-UP; AGY1-UP)

784B (PIN: 5RK1-UP)

784C (PIN: 2PZ1-UP)

785 (PIN: 8GB1-UP)

785B (PIN: 6HK1-UP)

785C (PIN: 1HW1-UP; APX1-UP)

785C HAA (PIN: 5AZ1-UP)

789 (PIN: 9ZC1-UP)

789B (PIN: 7EK1-UP)

789C (PIN: 2BW1-UP)

793 (PIN: 3SJ1-UP)

793B (PIN: 1HL1-UP)

793C (PIN: 4AR1-UP; ATY1-UP; 4GZ1-UP)

Introduction

This Special Instruction provides the necessary information in order to accurately locate the holes for the studs on the wheel assemblies for Off-Highway Trucks. This guideline will enable Caterpillar Dealers to make repairs to the wheel assemblies at a reduced cost to the customers. Successful repairs to the wheel assemblies depend on the following items: extent of the repair, repair methods and repair quality.

Suggested tools and equipment should be readily available for installation. If the tools and equipment are not available, assembly will be more difficult and more time will be necessary to complete the assembly.

Note: The illustrations in this publication are typical. The dimensions in the tables are for specific wheel assemblies. All of the dimensions that are listed are for the manufacturing and assembly of a new machine.

Do not attempt any assembly steps until you have read the information and you understand the information.

Refer to the appropriate service manual or the appropriate parts book for more information.

Initial Preparation

Inspection

The wheel assembly must be inspected before any welding procedure is performed. Inspection for cracks must be performed in order to prevent failure of the wheel assembly after the salvage operation. It may be necessary to remove any surface irregularities which might cover up unacceptable defects. The inspection method is the liquid dye penetrant and the magnetic particle inspection process.

Fixtures

A fixture may be fabricated in order to act as a pattern for the location of the holes. The fixture may be designed with larger holes in order to use drill guides.

Welding Operator Qualifications

All of the welders must be qualified in Shielded Metal Arc Welding (SMAW). The welders must be qualified to perform groove welding or fillet welding. Refer to the American National Standards Institute (ANSI)/American Welding Society (AWS) D1.1. Prior to welding, the process must have been used by the welders during the last six months. Welding qualifications must be documented and welding qualifications must be current.

The serial numbers of the individual wheels should be recorded for the following information: repair date, type of repair and name of the welder.

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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

Personal breathing protection should be worn by the welders. Personal breathing protection will prevent fumes from entering the lungs of the person that is welding. Use a 1U-8088 Type H Respirator for respiratory protection.

Preparation

1. Remove the following contaminants from the surface that will be repaired: oil, grease, paint, dirt and surface rust.

2. Cover the surfaces that have been machined.

3. Repairs should be made while the temperature of the wheel assembly is at 20 °C (68 °F). Protect the wheel assembly from drafts.

4. Use a rotary file in order to clean the bolt holes or holes for the studs. Use a rotary file to create a bevel around the edge of the holes.

5. Use a round copper plug in order to support the initial passes of the welding process.

Welding Procedure

Note: Use a shielding gas of CO² or 75% Argon and 25% CO² at 35 CFH for FCAW.

1. Ensure that the contaminants have been removed.

2. Preheat the area that will be welded in order to remove moisture. This will reduce the buildup of stress.

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NOTICE
Some wheels cannot be welded because the base metal is not applicable for wheel salvage.

3. Welds should be welded in sequence in order to reduce distortion of the wheel assembly. Deposit welding material from one side to the other side. Do not allow the welded area to become too hot. Maintain an interpass temperature of 65.6 °C (150 °F).

4. Allow the welds to cool. Grind the welds smooth.

Machining and Dimensions

Dimensions have been provided for the proper locations of the holes. Most of the hole locations are located from the center of the wheel.

A CNC machine can be used for locating the true position of the holes. A template could be used in order to locate the holes.

The following sections are divided by the models of the trucks. The sections provide the dimensions that are necessary to drill the holes.

Dimensions for the Front Wheels of the 769B, 769C and the 769D Off-Highway Trucks.

Illustration 1	g00698304
This is a view of the location of the holes for the front wheels of the 769B, 769C and the 769D Off-Highway Trucks.

Note: The dimension of the holes in Table 3 is 34.90 ± 0.02 mm (1.3740 ± 0.001 inch).

Dimensions for the Rear Wheels of the 769B, the 769C and the 769D Off-Highway Trucks.

Illustration 2	g00698342
This is a view of the location of the holes for the rear wheels of the 769B, the 769C and the 769D Off-Highway Trucks.

Note: The dimension of the holes in Table 4 is 34.90 ± 0.02 mm (1.374 ± 0.001 inch).

Dimensions for the Front Wheels of the 772, 772B, 773, 773B, 773D, 775B and the 775D Off-Highway Trucks.

Illustration 3	g00698359
This is a view of the location of the holes for the front wheels of the 772, 772B, 773, 773B, 773D, 775B and the 775D Off-Highway Trucks.

Note: The dimension of the holes in Table 5 is 34.90 ± 0.02 mm (1.374 ± 0.001 inch).

Dimensions for the Rear Wheels of the 772, 772B, 773, 773B, 773D, 775B and the 775D Off-Highway Trucks.

Illustration 4	g00698368
This is a view of the location of the holes for the rear wheels of the 772, 772B, 773, 773B, 773D, 775B and the 775D Off-Highway Trucks.

Note: The dimension of the holes in Table 6 is 34.90 ± 0.02 mm (1.374 ± 0.001 inch).

Dimensions for the Front Wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C and the 777D Off-Highway Trucks.

Illustration 5	g00698392
This is a view of the location of the holes for the front wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C and the 777D Off-Highway Trucks.

Note: The dimension of the holes in Table 7 is 34.90 ± 0.02 mm (1.374 ± 0.001 inch).

Dimensions for the Rear Wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C and the 777D Off-Highway Trucks.

Illustration 6	g00698403
This is a view of the location of the holes for the rear wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C and the 777D Off-Highway Trucks.

Note: The dimension of the holes in Table 8 is 34.90 ± 0.02 mm (1.374 ± 0.001 inch).

Dimensions for the Front Wheels of the 784B, 784C, 785, 785B, and the 785C Off-Highway Trucks.

Illustration 7	g00698406
This is a view of the location of the holes for the front wheels of the 784B, 784C, 785, 785B, and the 785C Off-Highway Trucks.

Note: The dimension of the holes in Table 9 is 27.04 ± 0.11 mm (1.065 ± 0.004 inch).

Dimensions for the Rear Wheels of the 784B, 784C, 785, 785B and the 785C Off-Highway Trucks.

Illustration 8	g00698421
This is a view of the location of the holes for the rear wheels of the 784B, 784C, 785, 785B and the 785C Off-Highway Trucks.

Note: The dimension of the holes in Table 10 is 27.04 ± 0.11 mm (1.065 ± 0.004 inch).

Dimensions for the Front Wheels of the 789, 789B and the 789C Off-Highway Trucks.

Illustration 9	g00698442
This is a view of the location of the holes for the front wheels of the 789, 789B and the 789C Off-Highway Trucks.

Note: The dimension of the holes in Table 11 is 27.04 ± 0.11 mm (1.065 ± 0.004 inch).

Dimensions for the Rear Wheels of the 789, 789B and the 789C Off-Highway Trucks.

Illustration 10	g00698452
This is a view of the location of the holes for the rear wheels of the 789, 789B and the 789C Off-Highway Trucks.

Note: The dimension of the holes in Table 12 is 27.04 ± 0.11 mm (1.065 ± 0.004 inch).

Dimensions for the Front Wheels and the Rear Wheels of the 793, 793B and the 793C Off-Highway Trucks.

Illustration 11	g00698459
This is a view of the location of the holes for the front wheels and the rear wheels of the 793, 793B and the 793C Off-Highway Trucks.

Note: The dimension of the holes in Table 13 is 27.04 ± 0.11 mm (1.065 ± 0.004 inch).

Information for Optional Replacement Studs