Procedure to Install a Rear Axle Tie Rod Stiffener to the 793F Off-Highway Truck {0679, 3030, 3064, 3160, 3260} Caterpillar

Off-Highway Truck/Tractor

793F (S/N: SND1-UP; SSP1-UP; RBT1-UP)

Introduction

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

This special instruction contains the necessary instructions for installation of a rear axle tie rod stiffener to the 793F Off-Highway Truck.

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When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the rear tow points. Install the rear tow point pins through the ends of the retaining cables. Failure to properly secure the body (bed) may result in personal injury or death.

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Personal injury can result from working with cleaning solvent. Because of the volatile nature of many cleaning solvents, extreme caution must be exercised when using them. If unsure about a particular cleaning fluid, refer to the manufacturer's instructions and directions. Always wear protective clothing and eye protection when working with cleaning solvents.

Required Parts

Required Tools

Important Safety Information

The following information is an explanation of various labels that are found in this document.

Warnings

The warning label informs the technician that an injury or death can occur as a result of a condition that may exist.

Notices

A notice informs the technician that component damage can occur as a result of a condition that exists.

Notes

A note contains general information for the technician about the operation that is being performed.

Proper repair is important to the safe operation and the reliable operation of this machine. This document outlines basic recommended procedures. Some of the procedures require special tools, devices, or work methods.

Before you perform any repairs or before you perform any maintenance, read all safety information. Understand all safety information before you perform any repairs or before you perform any maintenance.

Safety information is provided in this document and on the machine. If these hazard warnings are not heeded, bodily injury or death could occur to you or other persons.

The “Safety Alert Symbol” that is followed by a “Signal Word” identifies a hazard. “DANGER”, “WARNING”, and “CAUTION” are “Signal Words”.

Illustration 1	g00008666

The signal word “WARNING” has the following meanings:

• Pay Attention !

• Become Alert !

• Your Safety Is Involved !

The message that appears under the safety alert symbol explains the hazard.

Operations or conditions that may cause product damage are identified by "NOTICE" labels on the machine and in the service information.

The person that services the machine may be unfamiliar with many of the systems on the machine. Use caution when you perform service work. Special knowledge of the systems and of the components is important. Before you remove or disassemble any component, obtain knowledge of the system and knowledge of the component.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

Basic Precautions

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Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.

Always observe the list of basic precautions that follows:

Safety Signs

Safety signs include the items that follow: signs, information plates, and decals. Read all “Safety” signs on the machine before operating, lubricating, or repairing the machine. Understand all “Safety” signs on the machine before operating, lubricating, or repairing the machine. Replace any safety signs that are in the conditions that follow: damage, unreadable, and missing.

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.

Mounting and Dismounting

Use steps and handholds when you mount a machine. Also, use steps and handholds when you dismount a machine. Before you mount the machine, clean any mud or debris from steps, walkways, or work platforms. Always face the machine when you use steps, handholds, and walkways. When you cannot use the accesses on the machine, use ladders, scaffolds, or work platforms to perform safe repair operations.

Specifications for Cables, Chains, and Lifting Devices

Use approved cables, chains, and lifting devices to lift components. Refer to the manufacturer's weights 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 2	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.

Hot Fluids and Parts

To avoid burns, be alert for hot parts on machines which have been stopped and hot fluids in lines, tubes and compartments.

Be careful when you remove filler caps, breathers, and plugs on the machine. Hold a rag over the cap or plug to prevent being sprayed by pressurized liquids. When the machine has been stopped, the danger of hot fluids is greater.

Corrosion Inhibitor

Corrosion inhibitor contains alkali. Avoid contact with the eyes. Do not allow corrosion inhibitor to contact the skin for extended periods of time. Avoid repeated contact with the skin. Do not drink corrosion inhibitor. In case of contact, immediately wash skin with soap and water. For contact with the eyes, flush the eyes with large amounts of water for at least 15 minutes. Seek medical attention.

Batteries

Do not smoke when an inspection of the battery electrolyte level is made. Never disconnect any charging unit circuit or battery circuit cable from the battery when the charging unit is operating. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Do not allow battery electrolyte to contact skin or eyes. Battery electrolyte is an acid. In case of contact with battery electrolyte, immediately wash the skin with soap and water. For contact with the eyes, flush the eyes with large amounts of water for at least 15 minutes. Seek medical attention.

Pressurized Items

1. Always use a board or a piece of cardboard when you check for a leak. Leaking fluid under pressure can penetrate body tissue. Fluid penetration can cause serious injury and possible death. A pin hole leak can cause severe injury. If fluid is injected into your skin, you must get treatment immediately. Seek treatment from a doctor that is familiar with this type of injury.

2. Relieve all pressure in air, oil, or water systems before any lines, fittings, or related items are disconnected or removed. Always make sure that all raised components are blocked correctly. Be alert for possible pressure when you disconnect any device from a system that utilizes pressure.

3. Fuel lines that are damaged and fuel lines that are loose can cause fires. Lubrication lines that are damaged and lubrication lines that are loose can cause fires. Hydraulic lines, tubes, and hoses that are damaged can cause fires. Loose hydraulic lines, loose tubes, and loose hoses can cause fires. Do not bend or strike high-pressure lines. Do not install lines which have been bent or damaged. Check lines, tubes, and hoses carefully. Do not use your bare hand to check for leaks. If fluids are injected into your skin, you must get treatment immediately. Seek treatment from a doctor that is familiar with this type of injury.

4. Pressure air or water can cause personal injury. When pressure air or water is used for cleaning, wear a protective face shield, protective clothing, and protective shoes. The maximum air pressure for cleaning purposes must be below 205 kPa (30 psi). When you use a pressure washer, keep in mind that the nozzle pressures are high. The nozzle pressures are frequently above 13790 kPa (2000 psi). Follow all the recommended practices that are provided by the manufacturer of the pressure washer.

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.

Proper Welding Procedure on Machines and Engines with Electronic Controls

Proper precautions are necessary to prevent damage to electronic controls. When you weld on a machine with electronic controls, use the steps that follow:

1. Turn off the engine. Put the key start switch in the OFF position.

2. If the machine has a battery disconnect switch, open the switch. If the machine does not have a battery disconnect switch, disconnect the negative battery cable at the battery.

3. Attach the clamp for the ground cable as close as possible to the area that is being welded. This process will reduce the likelihood of damage from the welding current to the following components: bearings, hydraulic components, and electrical components. DO NOT weld plates to the frame for grounding/clamping purposes. Use existing blocks, brackets, bosses, and so on, to attach the clamp.

   Note: Do NOT use electrical components as a ground point for the welder. Do NOT use ground points for electronic components as a ground point for the welder.

4. Protect the wiring harnesses and machine surfaces from sparks and welding spatter.

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.

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 and the manufacturer's 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. The use of higher parameters than specified for welding in the flat position is acceptable.

Use a polarity setting of DC reverse polarity. Remove the slag after each welding pass. 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 shall 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) when not in use. If low hydrogen electrodes get damp, scrap the low hydrogen electrodes or recondition the low hydrogen electrodes to the manufacturer's 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 shall not exceed two times the electrode diameter.

Weld Inspection and Acceptance Criteria

General Weld Repair

1. Remove any components that prevent access to the cracked weld.

2. Refer to "Welding Electrodes and Parameters" Section in this Special Instruction.

3. Use dye penetrant (PT) or magnetic particle (MT) to identify the extent and/or length of the necessary repair.

4. Protect machined surfaces from sparks and weld debris.

5. Ensure that the base material is at a minimum temperature of 15.6° C (60° F) before welding. Ensure that a minimum temperature of 15.6° C (60° F) is maintained throughout the entire welding procedure.

   Note: If preheat/interpass/postheat requirements are specified in document, they shall supersede.

6. The crack (and sound metal 50 mm (2.00 inch) beyond each end of the crack) shall be removed by gouging and/or grinding. Caution shall be used to avoid excessive removal of the surrounding base material. Areas that are gouged by air carbon arc torch shall be later ground and cleaned prior to welding to remove all carbon absorption or contamination. Gouged areas requiring rewelding shall have a root radius of not less than 5 mm (0.20 inch) and a Single V - 60 degree included angle joint preparation to allow the welder reasonable access to reinstate the weld.

7. Use PT or MT to inspect the gouged and ground area to ensure that the crack has been removed before welding commences.

8. Repair the prepared groove utilizing the recommendations provided in the "Welding Electrodes and Parameters" Section in this Special Instruction.

   • Remove the slag after each weld pass

   • Utilize stringer bead technique

   • All vertical welding (SMAW and FCAW) shall be vertical up progression

   • Stagger weld starts and stops when completing multi-pass fillet welds and groove welds

9. Clean the weld area. Inspect the area that was welded. All weld quality shall conform to the criteria specified in the "Weld Inspection and Acceptance Criteria" section in this Special Instruction.

Procedure to Install the Rear Axle 464-9177 Tie Rod Stiffener (Double Adjusting)

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Illustration 3	g03744147
View of the LH side of the transmission

1. Remove and discard three bolts (A).
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   Illustration 4	g03747662
   View of the LH side of the transmission (1) Washer (2) Hard washer (3) Plate assembly (8) Bolt

2. Install plate assembly (3).
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   Illustration 5	g03747665
   Side view of the LH side of the transmission (1) Washer (2) Hard washer (3) Plate assembly (8) Bolt

3. Starting at the bottom hole on plate assembly (3) insert washer (1), bolt (8), and hard washer (2) on the back side of plate assembly (3). Tighten bolts (8) to hand tight.

   Note: Ensure that hard washer (2) is between plate assembly (3) and the transmission.

4. Check clearances to ensure that there is no cast case contact.

5. Torque bolts (8) to 460 ± 60 N·m (339 ± 44 lb ft).
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   Illustration 6	g03747670
   View of the LH side of the transmission (3) Plate assembly (4) Pin (6) Tie rod assembly (7) Pin

6. Install tie rod assembly (6) onto plate assembly (3) and insert pin (4) and pin (7).

   Note: Ensure that the RH thread of tie rod assembly (6) is on the rear axle side. "RH" is stamped on tie rod assembly (6).

7. Install plate assembly (5) onto tie rod assembly (6) and insert pin (4) and pin (7).
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   Illustration 7	g03825453
   View of tie rod assembly against rear axle housing (AA) 20 mm (0.80 inch) (B) Existing block (5) Plate assembly (6) Tie rod assembly

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   Illustration 8	g03747679
   View of tie rod assembly against rear axle housing (BB) 264 mm (10.40 inch) (CC) Center line of the rear axle housing (5) Plate assembly (6) Tie rod assembly

8. Swing tie rod assembly (6) towards the rear axle housing until the bottom of plate assembly (5) meets the rear axle housing. Plumb and level with plate assembly (3) installed onto the transmission.

   Refer to the dimensions in Illustration 7 and Illustration 8.

9. Adjust tie rod assembly (6) by hand so that plate assembly (5) is flat on the rear axle housing.

   Note: Grinding of the rear axle housing may be required.

10. Tack weld plate assembly (5) to the rear axle housing.

11. Remove tie rod assembly (6).

12. Prepare for welding and remove/protect surrounding components.
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    Illustration 9	g03825655

13. Weld plate assembly (5) to the rear axle housing, using the weld dimensions in Illustration 9. Do not start/stop weld at mid corner.

    Note: Weld may be accomplished with multiple passes to obtain 10 mm (0.4 inch) fillet.

14. Inspect the weld to ensure that all weld quality meets or exceeds the requirements shown in the "Welding Specifications and Qualifications" section.

15. Install tie rod assembly (6) onto plate assembly (3) and plate assembly (5). Insert pins (4) and pins (7).

    Note: Ensure that the RH thread of tie rod assembly (6) is on the rear axle side. "RH" is stamped on tie rod assembly (6).

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    Illustration 10	g03747686
    View of tie rod assembly (C) Angle meter (6) Tie rod assembly

16. Place angle meter (C) on tie rod assembly (6) flat.

17. When facing towards the rear of the machine, turn tie rod assembly (6) clockwise so that only tension is applied. Once tie rod assembly (6) is hand tight, rotate an additional 120 degrees.

18. Tighten jam nuts to 60 ± 12 N·m (44 ± 9 lb ft).

Procedure to Install the Rear Axle 514-0301 Tie Rod Stiffener (Single Adjusting)

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Illustration 11	g06378427
View of the LH side of the transmission (A) Bolts

1. Remove and discard three bolts (A).
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   Illustration 12	g06378428
   View of the LH side of the transmission (1) 8T-0360 Bolt (2) 198-4769 Washer (3) 226-4192 Hard Washer (4) 459-8466 Plate As

2. Install plate assembly (4).
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   Illustration 13	g06378429
   Side view of the LH side of the transmission (1) 8T-0360 Bolt (2) 198-4769 Washer (3) 226-4192 Hard Washer (4) 459-8466 Plate As

3. Starting at the bottom hole on plate assembly (4), insert washer (2), bolt (1), and hard washer (3) on the back side of plate assembly (4). Tighten bolts (1) to hand tight.

   Note: Ensure that hard washer (3) is between plate assembly (4) and the transmission.

4. Check clearances to ensure that there is no cast case contact.

5. Torque bolts (1) to 460 ± 60 N·m (339 ± 44 lb ft).
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   Illustration 14	g06378430
   View of the LH side of the transmission (4) 459-8466 Plate As (5) 459-8467 Pin (6) 8D-3791 Pin (7) 514-0301 Tie Rod

6. Install tie rod (7) onto plate assembly (4) and insert pin (5) and pin (6).

   Note: Place tied rod (7) ends in clevises on transmission and axle housing with tie rod (7) closest to the adjuster sleeve in the transmission clevis.

7. Install plate assembly (4) onto tie rod (7) and insert pin (5) and pin (6).
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   Illustration 15	g06378431
   View of tie rod assembly against rear axle housing (D1) 20 mm (0.8 inch) (B) Existing block (7) 514-0301 Tie Rod (8) 460-4882 Plate As

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   Illustration 16	g06378432
   View of tie rod assembly against rear axle housing (D2) 264 mm (10.4 inch) (C) Center line of the rear axle housing (7) 514-0301 Tie Rod (8) 460-4882 Plate As

8. Swing tie rod (7) towards the rear axle housing until the bottom of plate assembly (8) meets the rear axle housing. Plumb and level with plate assembly (4) installed onto the transmission.

   Refer to the dimensions in Illustration 15 and Illustration 16.

9. Adjust tie rod (7) by hand so that plate assembly (8) is flat on the rear axle housing.

   Note: Grinding of the rear axle housing may be required.

10. Tack weld plate assembly (8) to the rear axle housing.

11. Remove tie rod (7).

12. Prepare for welding and remove/protect surrounding components.
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    Illustration 17	g06378433

13. Weld plate assembly (8) to the rear axle housing, using the weld dimensions in Illustration 17. Do not start/stop weld at mid corner.

    Note: Weld may be accomplished with multiple passes to obtain 10 mm (0.4 inch) fillet.

14. Inspect the weld to ensure that all weld quality meets or exceeds the requirements shown in the "Welding Specifications and Qualifications" section.

15. Install tie rod (7) onto plate assembly (4) and plate assembly (8). Insert pins (5) and pins (6).

    Note: Place tied rod (7) ends in clevises on transmission and axle housing with tie rod (7) closest to the adjuster sleeve in the transmission clevis.

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    Illustration 18	g06425685
    View of tie rod assembly (D) Angle meter (7) Tie rod

16. Place angle meter (D) on tie rod (7) flat.

17. When facing towards the rear of the machine, turn adjuster sleeve of tie rod (7) clockwise so that only tension is applied. Tighten tie rod (7) to 200 ± 40 N·m (148 ± 30 lb ft). Refer to Illustration 18.

18. Then rotate adjuster sleeve of tie rod (7) counter-clockwise until tension is removed.

19. Then rotate adjuster sleeve of tie rod (7) clockwise and tighten tie rod (7) to 100 ± 20 N·m (74 ± 15 lb ft). Then rotate adjuster sleeve of tie rod (7) an additional 30 degrees.

20. Lock adjuster sleeve by tightening clamp bolt to 115 ± 20 N·m (85 ± 15 lb ft).

    Note: With a paint marker or similar marking method, draw a line across the adjusting sleeve and onto the tube and rod eye. This marking can be used as a visual reference to verify that the adjustment sleeve has not moved.