Assembly Procedure for the 797F Off-Highway Truck High Performance (HP) Body {0374, 7000, 7250, 7258, 7960} Caterpillar

Off-Highway Truck/Tractor

797F (S/N: LAJ1-UP; WSP1-UP; LTZ1-UP)

Introduction

This manual contains information to assemble the 438-6000 Body and Canopy As for the 797F Off-Highway Truck.

This Special Instruction must be used with Special Instruction, SEHS0328, "Assembly Procedure for the 797F Off-Highway Truck High Performance (HP) Body" poster.

Do not perform any procedures or order any parts until this publication is read thoroughly.

The recommended tools and equipment should be present during assembly. If the recommended tools or equipment is not present, assembly will be more difficult and more time will be necessary to complete the assembly.

A flat, smooth, drained area 55/75 m (180/246 ft) by 55/75 m (180/246 ft) is needed for the assembly.

Note: An enclosed building is recommended for the welding of any truck body. The dispersing of the shielding gases away from the welding area must be kept to a minimum.

Safety

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Personal injury or death can result from improper assembly procedures. Do not attempt any assembly until you have read and understand the assembly instructions.

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Personal injury or death can result from lifting a heavy assembly. The heavy assembly can fall if using an incorrect hoist to lift the load. Be sure the hoist has the correct capacity to lift a heavy assembly. Approximate weight of the assembly is given below.

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Make sure the lifting cables and other lifting devices are strong enough to support the machine.

Protective Equipment

When you work around the machine, always wear protective equipment that is required by the job conditions. Protective equipment includes the items that follow: hard hat, protective glasses, and protective shoes. In particular, wear protective glasses when you use a hammer or when you use a sledge hammer. When you weld, use the appropriate protective equipment that is required by the job conditions. Protective equipment for welding includes the items that follow: gloves, welding hood, goggles, and apron. Do not wear loose clothing or jewelry that can catch on parts of the machine.

Reference Section

Reference: Operation and Maintenance Manual, SEBU8417

Reference: Special Instruction, REHS5063, "Assembly Procedure for the 797F and the 797F XQ Off-Highway Truck"

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

Reference: Tool Operating Manual, NEHS1120, "Truck Body Lifting Pins"

Reference: Special Instruction, SEHS0328, "Assembly Procedure for the 797F Off-Highway Truck High Performance (HP) Body" (Poster)

Caterpillar Channel 1 Video

To provide addition clarification and details, videos have been created outlining the critical steps in the welding process. Reviewing the videos is recommended prior to starting the repair process.

Note: A CWS login is required to access Caterpillar Channel 1. Scan the QR code below with a QR enabled device or copy the link that follows.

Illustration 1	g06347025

Reference: For more information, refer to SEHS0327 , "Assembly Procedure for the 797F Off-Highway Truck High Performance (HP) Body" on Caterpillar Channel 1.

Parts List

Weights and Required Tooling

The approximate weight of the truck body depends on the configuration of the truck body. Use one or two mobile cranes to lift the truck body as needed.

Table 2 contains examples of the approximate weights of the truck body, and the canopy assemblies.

Note: The weights that are listed in this document are only approximate weights. Refer to the machine shipping order (MSO) that was shipped with the truck body for specific weights. Use the MSO to determine lifting requirements.

Approved Inspection Methods

Visual inspection by qualified personnel is the most useful method. Ultrasonic inspection can be done on castings and welds with convenient geometry. Use the magnetic particle inspection process or the dye penetrant inspection process in the other areas. Do not use the magnetic particle inspection process around components that will be affected by magnetism. Do not use the dye penetrant inspection process around components that will be affected by the dye penetrant solution.

Welding Specifications and Qualifications

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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 kill. Read and understand the manufacturer's instruction and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and the general area. Wear correct eye, ear and body protection. Do not touch live electric parts. Refer to the American National Standard Z49.1, "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CFR 1910, available from U.S. Dept. of Labor, Washington D.C. 20210.

Note: Personal breathing protection should be worn by the personnel that are welding. Personal breathing protection will prevent fumes from entering the lungs of the person that is welding. Use a 237-5181 Respirator for breathing protection.

Qualifications

Welders must be qualified for the appropriate type of weld that is being performed. Welders must be qualified for the appropriate position of weld that is being performed. Welders must be qualified for the welding process that is being utilized: Shielded Metal Arc Welding (SMAW) and Flux Cored Arc Welding (FCAW). Refer to Specification ANSI/AWS D1.1 for information that regards qualification requirements. The welders must have used the process at some time within the last 6 months. The welders must complete the process of certification if the welders have not used the welding processes for 6 months.

Area Preparation

The area to be welded shall be clean, dry, and free of the following contaminants:

• Oil

• Grease

• Paint

• Dirt

• Rust

• Any fluids or moisture

All welding shall be conducted on base material heated and maintained at a minimum temperature of 15.6° C (60° F).

Note: Heating instructions (preheat, interpass, and postheat) for any specific repair shall override the minimum 15.6° C (60° F) requirement.

Note: Heat distortion of the base metal is possible when you weld. Avoid excessive heating of the base metal.

Attach the welding ground cable directly to the base metal. Protect machined surfaces from sparks. Protect the machined surfaces from the welding spatter.

Welding Electrodes and Parameters

Flux Cored Welding Electrode for the FCAW Process

Use the Flux Cored Arc Welding (FCAW) with E71T-1 H8 (ANSI/A5.20) welding electrode. Use the manufacturers shielding gases that are specified (typically 75% argon and 25% carbon dioxide). The H8 implies that the electrode is designed to provide less than 8 ml/100 g of diffusible hydrogen in the weld deposit. The weld that is deposited by the flux cored welding electrode will have the following minimum mechanical properties:

The tables that follow show the recommended parameter ranges for out of position welding in the field for two different flux cored welding electrode diameters.

Note: The settings listed above are recommendations-based on experience from welding in the horizontal, vertical-up, and overhead positions. Slight changes in the voltage and amperage may be necessary due to welding position and various formulations by different electrode manufacturers. Higher parameters are acceptable to use for welding in the flat position.

Use a polarity setting of DC reverse polarity. Remove the slag after each pass of the welding electrode. The fast freezing characteristics of flux cored welding electrode increases the possibility of evolving gas that is trapped in the weld. Control the size of the weld to reduce the possibility of evolving gas that is trapped in the weld. The maximum size weld per pass should be equivalent to that of a 8.0 mm (.32 inch) fillet weld.

Low Hydrogen Electrodes for the SMAW Process

As an alternative process or when wind conditions are a factor, use SMAW and low hydrogen electrodes that meet the following requirements.

Low hydrogen electrodes must be stored in an electrode oven at 120 °C (250 °F). If low hydrogen electrodes get damp, scrap the low hydrogen electrodes or recondition the low hydrogen electrodes to the manufacturers specifications.

The table that follows shows the settings for the welding current based on electrode diameter.

Use a polarity setting of DC reverse polarity. Remove the slag after each pass of the welding electrode. The width of the weld should not exceed two times the electrode diameter.

Weld Inspection and Acceptance Criteria

To verify the quality of the weld, refer to Figure 27 from Caterpillar Specification 1E99 which is shown above.

Weld Types and Locations

Reference: Refer to Special Instruction, SEHS0328, "Assembly Procedure for the 797F Off-Highway Truck High Performance (HP) Body" (Poster) for the proper weld types and locations. This Special Instruction will also show the locations of all field assembly components.

Welding Instructions

General Preheat Instructions for Truck Body Field Assembly

The following materials are used to fabricate the large mining truck (LMT) truck bodies :

• 400 Brinell hardness number (BHN) steel. Base body plates, canopy wrapper, and interior transition plates.

• 450 Brinell hardness number (BHN) steel. Liner plates, rock boxes, and wear bars.

Base material must be a minimum temperature of 16° C (60° F) before welding and during welding. Prior to work engagement, the recommended procedure is to apply heat to weld joints to sweat out residual build-up of condensation.

Before welding on the truck body, verify the materials that are used to fabricate your particular truck body. There are specific welding procedures for each material. Refer to the following instructions to weld the materials during the assembly of the truck body successfully.

400 Brinell Hardness or 450 Brinell Hardness Material

The following procedure covers the requirements for welding the assembly of the LMT truck bodies. This instruction is to provide an overall guideline of the recommended preheat requirements. This instruction applies to the welding procedure for truck bodies that are fabricated with 400 BHN steel or 450 BHN steel. Refer to "Welding Specifications and Qualifications" for qualifications, safety, and welding electrode parameters. Attach the welding ground cable directly to the body assembly. Protect all the machined areas from sparks and spatter that are produced by welding, chipping, and grinding operations.

Proper preparation of the welding area must be conducted prior to welding. All weld joints and welding areas must be exceptionally clean. Clean the welding area with a grinder. Completely remove all paint, rust, scale, slag, dirt, moisture, and grease before welding.

Tight fit up of the body assemblies is important. Ensure that every effort is made to minimize the gap spacing. Minimizing the gap spacing reduces the residual stresses.

To minimize the possibility of cracking, use large tack welds. A maximum tack weld size of 6 mm (0.25 inch) fillet weld with a length of 75 mm (3 inch) is recommended.

Preheating is most critical during the tack welding procedure and during the welding of the root pass.

Illustration 2	g03032696
Typical view of a Tiger Torch

A Tiger Torch can be used to preheat the material that is welded. Refer to Table 10 for the required preheat temperature of the material.

Ensure that the weld groove and 75 mm (3 inch) in each direction from the weld joint is preheated to the specified temperature. Verify the preheat temperature with a 164-3310 Infrared Thermometer or with a temperature stick.

The minimum inter-pass temperature should equal the preheat temperature. The maximum inter-pass temperature should not exceed 250 °C (480 °F).

Note: The above preheat and inter-pass temperatures are for mild restraint to moderate restraint. If clamping devices are utilized to reduce the gap spacing to less than 3 mm (0.12 inch), use the next higher preheat temperature, when possible. Additional stresses are offset by using the next higher preheat temperature.

Note: If the ambient temperature is below 0 °C (32 °F), then the initial preheat temperature should be raised to 121 °C (250 °F). The raised preheat temperature needs to be a minimum of 75 mm (3 inch) in each direction from the weld joint to avoid the heat sink effect of the floor plates.

All welded areas must be inspected. Hydrogen induced cracking normally occurs within 72 hours of welding. Allow the welded areas to cool for 48 hours to 72 hours prior to performing a visual inspection. If any welding areas are suspected of being cracked during the visual inspection, the welding areas must be inspected. Use the dye penetrant process or the magnetic particle inspection process to inspect the welding areas. The welds shall be free from the following defects: cracks, porosity, undercut and incomplete fusion. All weld quality shall conform to American National Standards Institute (ANSI)/American Welding Society (AWS) D1.1.

Specifications for Cables, Chains, and Lifting Devices

Use approved cables, chains, and lifting devices to lift components. Refer to the manufacturers weight's to determine the application when you select the following items: cable, chain, and lifting devices. When you lift a component, the lift angle is critical. Refer to the Illustration that follows to see the effect of the lift angle on the working load limit.

Note: The lifting devices that are shown in this publication are not Caterpillar parts.

Note: Ensure that the hooks are equipped with a safety latch. Do not place a side load on the lifting eyes during a lifting operation.

Illustration 3	g00629745
Lift angles for lifting slings. (A) The load capacity is 100% of the working load limit for the sling. (B) The load capacity is 86% of the working load limit for the sling. (C) The load capacity is 70% of the working load limit for the sling. (D) The load capacity is 50% of the working load limit for the sling.

Lifting Eye Locations

For handling purposes, lifting eyes are at convenient locations. Only use the following lifting eyes. Once the assembly is complete, the lifting eyes may be removed.

Note: If the body is being shipped, some lugs or lifting eyes may be needed for tie downs.

Refer to the following graphic for the lifting eye locations for the 438-6000 Body and Canopy As.

Illustration 4	g03890965
View of the lifting eye locations on the right-hand and left-hand side of the body assembly

Illustration 5	g03890984
View of the lifting eyes locations on the canopy and inside the body assembly

Illustration 6	g03890991
View of the lifting eyes locations on the bottom of the body assembly

Assembly Procedure

Required Parts

Preparation

Ensure all the components for the body have been unloaded from the shipping trucks. Ensure that the build site is suitable and safe.

Note: The serial number of the truck body is stamped on the edge of each section. Before assembling the body, make sure that the serial numbers for all the components match.

Grind and/or sand blast all welding areas of the truck body assemblies. Grind and/or sand blast all welding areas of the components for the truck body assemblies. Completely remove all paint, rust, scale, slag, dirt, moisture, and grease before tack welding and finish welding.

Note: Before welding, preheat the welding areas to the proper temperature. Refer to "Welding Instructions". Use 164-3310 Infrared Thermometer to check for the proper preheat temperature.

Reference: "Welding Instructions" and "Welding Specifications and Qualifications"

Reference: "Weld Types and Locations" for the proper welds and the locations of all field assembly components.

Installation of the Body Assembly (RH) and Body Assembly (LH) to Center Body Assembly

Note: Before lifting any component of the truck body, refer to Table 2 for component weight. Also, refer to "Specifications for Cables, Chains, and Lifting Devices".

Reference: Refer to "Lifting Eye Locations" for the location of the lifting eyes for the truck body that is being assembled.

1. Position two suitable cranes or lifting devices near the work area.
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   Illustration 7	g03891529
   Center Body Assembly

2. Use a suitable lifting device to position the center body assembly. Position the center body assembly onto suitable supporting devices or wood blocks inside the work area. The approximate weight of right-hand body assembly is 17759 kg (39152 lb).

   Note: Position suitable supporting devices or wood blocks on a level surface to support the front and rear of center body assembly.

3. Verify that the floor of the center body assembly is level in all directions.

4. Lower center body assembly onto the wood blocks and remove all lifting devices.
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   Illustration 8	g03891540
   Right-hand Body Assembly

5. Use suitable lifting device to position the right-hand body assembly onto suitable supporting devices or wood blocks inside the work area. The approximate weight of right-hand body assembly is 9813 kg (21634 lb).

6. Locate the right-hand body assembly into the work area.

7. Position suitable supporting devices or wood blocks on a level surface to support the right-hand body assembly.

   Note: Ensure that the right-hand body assembly is level with the center body assembly

8. Position the right-hand body assembly against the center body assembly.

   Note: The alignment plates ease the alignment of the right-hand body assembly to the center body assembly.

9. Lower the right-hand body assembly onto the wood blocks and remove all lifting devices.

10. Secure the right-hand body assembly to the center body assembly.
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    Illustration 9	g03891563
    View of the Body Assembly (4) 442-0849 Body (5) 442-0850 Body (6) 442-0851 Body (13) 7X-0851 Nut (15) 8T-0674 Bolt

11. Align the lugs on center body assembly (4) to the lugs on body assembly (RH) (5).

12. Install eight bolts (15) and eight nuts (13).
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    Illustration 10	g03888577
    Typical view of 1U-9204 Lever Puller Hoist Gp

13. If necessary, a 1U-9204 Lever Puller Hoist Gp can be used to align the body assemblies.

14. Once the assemblies are aligned, tighten eight bolts (15) and eight nuts (13).

15. Ensure that body assembly (RH) (7) is level with center body assembly (6).
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    Illustration 11	g01283695

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    Illustration 12	g02726495

16. If necessary, use alignment blocks and wedges to level body assembly (RH) (5) with center body assembly (6). Refer to Illustrations 11 and 12.

17. Finish weld the right-hand body assembly to the center body assembly.

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 13	g03891896
    View of positioning left-hand body assembly onto the center body assembly

    Note: Use a suitable lifting device to lift the body assembly. Refer to Tool Operating Manual, NEHS1120, "Truck Body Lifting Pins".

18. Attach two suitable lifting devices to the body assembly. Secure the lifting devices to a suitable hoist. The approximate weight of right-hand body assembly is 9813 kg (21634 lb).

19. Locate the left-hand body assembly into the work area.

20. Position suitable supporting devices or wood blocks on a level surface to support the left-hand body assembly.

    Note: Ensure that the left-hand body assembly is level with the center body assembly

21. Position the left-hand body assembly against the center body assembly.

    Note: The alignment plates ease the alignment of the left-hand body assembly to the center body assembly.

22. Lower the left-hand body assembly onto suitable supporting devices or wood blocks and remove all lifting devices.

23. Secure the left-hand body assembly to the center body assembly.

24. Repeat Step 12 through Step 16 for body assembly (LH) (8).

25. Finish weld the left-hand body assembly to the center body assembly.

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 14	g03891996
    (9) 442-0985 Plate

26. Use a suitable lifting device and position two plates (9) between the three body assembly sections. The approximate weight of plates (9) is 26 kg (57 lb).

27. Finish weld plates (9).

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 15	g03892002
    (7) 442-0852 Canopy As (13) 7X-0851 Nut (15) 8T-0674 Bolt

28. Attach a suitable lifting device to the canopy assembly. The approximate weight of the canopy assembly is 3337 kg (7357 lb).

29. Locate the front canopy assembly into the work area.

30. Align the canopy to the body assembly.

    Note: When you position the canopy, a guide line may be necessary.

31. Hold the canopy assembly in place with the lifting device until the canopy is assembled to the body assembly.

32. Secure the canopy assembly to the body assembly using four bolts (15) and four nuts (13).

33. Finish weld the canopy assembly to the body assembly

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 16	g03892076
    (12) 461-8902 Plate

34. Install plates (12) onto the body assembly.

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 17	g03892086

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    Illustration 18	g03892136

35. Install four guard assemblies (8) onto the canopy assembly.

    Note: Use the tabs shown in Illustration 17 to guide the guards into position.

36. Finish weld the guard assemblies (8) into position.

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 19	g03892451
    (11) 457-4431 Plate (17) 8T-4183 Bolt (18) 8T-4223 Hard Washer

37. Install one plate (11) onto each side of the body assembly and secure into position using two hard washers (18) and two bolts (17).
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    Illustration 20	g03892524
    (10) 442-0987 Plate As

38. Use a suitable lifting device to position two plate assemblies (10) onto the underside of the body.

39. Finish weld plate assemblies (10) in place.

    Note: Refer to "Weld Types and Locations" for this procedure.

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    Illustration 21	g03892603
    (2) 347-5985 Bar As

40. Position 2 bar assemblies (2) onto the underside of the body.

41. Finish weld bar assemblies (2) in place.

    Note: Refer to "Weld Types and Locations" for this procedure.

Miscellaneous

1. Remove all lifting eyes, alignment blocks, lugs, stiffeners, and braces from the truck body if shipping is not required. Grind the welds smooth prior to touch up painting and installation to the chassis.

2. Ensure that all welds have been inspected.

   Reference: "Welding Specifications and Qualifications" and "Welding Instructions"

3. Clean the entire truck body.

4. Repaint the truck body, as needed.