- Off-Highway Truck/Tractor:
- 777D (S/N: FKR1-UP)
Introduction
ReferenceDisassembly and Assembly, RENR8432, "777D Off-Highway Truck Cab - Remove"
ReferenceDisassembly and Assembly, RENR8432, "777DOff-Highway Truck Cab - Install"
This Special Instruction provides information on the area, of the upper suspension mounting that should be inspected for weld defects.
Note: For those trucks that did not have TTD (TIG Toe Dress) completed at the factory, it can be done prior to cracking to ensure a longer fatigue life at this location. Refer to the Proactive Preventative Action section to perform the TTD.
Proper Cleaning for Inspection
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To prevent personal injury or death, do not work under the machine with the body (bed) raised. When it is necessary to work under the machine with the body (bed) raised, install the body (bed) retaining cable end through the rear tow pin at the rear of the machine. |
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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. |
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| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
Before you inspect the area, clean the area with an appropriate high-pressure washer. Be careful not to damage wires or other components. Use an appropriate degreaser to remove any oil or grease from the frame assembly. Use a wire brush or a scraper to remove excessive dirt and grease. Make sure that the substances that follow are removed from the area that will be inspected.
- Oil
- Grease
- Dirt
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.
Inspection Intervals
Inspections of the frame assembly for cracks should be conducted during regular maintenance intervals. Areas to be inspected are blocked by one or more components. If the component that is blocking the frame is removed, an inspection of that area should be performed. Take advantage of the opportunity to inspect those parts of the frame assembly that are exposed whenever components are removed. As an example, if the hydraulic tank is ever removed, the area behind the hydraulic tank should be cleaned and inspected. Refer to Operation and Maintenance Manual, SEBU8308, "777D Off-Highway Truck", "Frame - Clean/Inspect" for the proper inspection intervals.
Important Safety Information
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".
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| 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 any component or before you 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. You must determine that the tools, procedures, work methods, and operating techniques are safe. You must determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, you must 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. |
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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 are welding, 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 in order to lift components. Refer to the manufacturer weight's in order 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 in order 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.
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| 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 in order 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
- 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.
- 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.
- 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. Hydraulic lines, 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.
- 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 of 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. |
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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:
- Turn off the engine. Put the key start switch in the OFF position.
- 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.
- Connect the ground cable for the welder directly to the actual machine component that will be welded. Attach the clamp for the ground cable as close as possible to the area that is being welded. This process will reduce the chance of damage from welding current to the components that follow: bearings, hydraulic components and electrical components.
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.
- Protect the wiring harnesses from the 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.
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 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:
| Mechanical Properties from Flux Cored Welding Electrode That Is Classified as "ANSI/AWS A5.20 E71T-1 H8" | |
|---|---|
| Tensile Strength | 480 MPa (70000 psi) |
| Yield Strength | 400 MPa (58000 psi) |
| Elongation | 22% |
| Impact Toughness | 27 J @ -18 °C (20 ft lb @ -0 °F) |
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.
| Welding Current for Flux Cored Welding Electrode that Is 1.2 mm (0.045 inch) |
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| Wire Feed Rate | Voltage | Amperage |
7620 mm (300 inch) Per Minute to 10,160 mm (400 inch) Per Minute |
24 to 28 | 190 to 240 |
| Welding Current for Flux Cored Welding Electrode that Is 1.4 mm (0.052 inch) |
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|---|---|---|
| Wire Feed Rate | Voltage | Amperage |
5080 mm (200 inch) Per Minute to 6350 mm (250 inch) Per Minute |
23 to 27 | 180 to 220 |
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 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 in order 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.
| Mechanical Properties of Welds from Low Hydrogen Electrodes That Are Classified as "ANSI/AWS A5.1 E7018" | |
|---|---|
| Tensile Strength | 480 MPa (70000 psi) |
| Yield Strength | 400 MPa (58000 psi) |
| Elongation | 22% |
| Impact Toughness | 27 J @ -29 °C (20 ft lb @ -20 °F) |
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 manufacturer's specifications.
The table that follows shows the settings for the welding current based on electrode diameter.
| Welding Current for Low Hydrogen Electrodes | |
|---|---|
| Diameter | Amperage Rating |
| 3.2 mm (1/8 inch) | 105-155 |
| 4.0 mm (5/32 inch) | 130-200 |
| 4.8 mm (3/16 inch) | 200-275 |
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
| Defect Name | ISO 6520 Defect Reference Number | Remarks | Defect Limit |
| Cracks - Longitudinal, Transverse, Radiating, Crater, Disconnected, Branching | 1011, 1012, 1013, 1014, 1023, 1024, 1031, 1033, 1034, 1045, 1046, 1047, 1051, 1053, 1054, 1061, 1063, 1064 | -- | Not Permitted |
| Crack - Transverse | 1021 | Hard Surfacing Welds Only | Permitted |
| Crack - Transverse | 1021 | Joining Welds | Not Permitted |
| Porosity | 2011, 2012, 2014, 2017 | Maximum Diameter for a Single Pore | 1 mm (0.040 inch) |
| Maximum Pores in Any 300 mm (11.81 inch) Length of Weld |
6 | ||
| Maximum Number of Pores in Any 50 mm (2.0 inch) of Weld Length for Welds Less Than 300 mm (11.81 inch) in Length |
1 | ||
| Clustered Porosity | 2013 | Maximum Length of Cluster in Any Weld | 3 mm (0.120 inch) |
| Elongated Cavities | 2015 | Maximum Height or Width | 3 mm (0.120 inch) |
| Maximum Length for Any Single Discontinuity | 25 mm (1.00 inch) |
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| Maximum Length in Any Weld | 10% of Weld Length | ||
| Elongated Cavities | 2016 | Maximum Dimension of Any Single Cavity | 3 mm (0.120 inch) |
| Maximum Total Length of Affected Area in Any Weld | 10% of Weld Length Not to Exceed 25 mm (1.00 inch) |
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| Shrinkage Cavities | 2021, 2024, 2025 | Maximum Diameter or Length | 1 mm (0.040 inch) |
| Slag or Flux Inclusions | 3011, 3012, 3014, 3021, 3022, 3024 | Maximum Height or Width | 1 mm (0.040 inch) |
| Maximum Length for Any Single Discontinuity | 25 mm (1.00 inch) |
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| Maximum Length in Any Weld | 10% of Weld Length | ||
| Oxide Inclusions | 3031, 3032, 3033 | Maximum Height or Width | 1 mm (0.040 inch) |
| Maximum Length for Any Single Discontinuity | 25 mm (1.00 inch) |
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| Maximum Length in Any Weld | 10% of Weld Length | ||
| Puckering (Oxide Inclusion - Aluminum) | 3034 | -- | Not Permitted |
| Metallic Inclusion | 3041, 3042, 3043 | -- | Not Permitted |
| Lack of Fusion | 4011, 4012, 4013 | Visual (Breaking the Surface) | Not Permitted |
| Subsurface Maximum Height or Width | 1 mm (0.040 inch) |
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| Subsurface Maximum Length for Any Single Discontinuity | 25 mm (1.00 inch) |
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| Maximum Length in Any Weld | 10% of Weld Length | ||
| Lack of Penetration | 402, 4021 | Maximum Reduced Penetration | 10% of Nominal Penetration Not to Exceed 1 mm (0.040 inch) |
| Maximum Allowed Total Length of Reduced Penetration | 10% of Weld Length | ||
| Undercut | 5011, 5012, 5013, 5014, 5015 | Maximum Depth Measured From Plate Surface - Any Length | 0.5 mm (0.020 inch) |
| Excess Weld Metal - Groove Weld Reinforcement (Convexity) | 502 | Any Length | -- |
| Weld Face Width 5 mm (0.20 inch) or Less |
1 mm (0.040 inch) |
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| Weld Face Width Over 5 mm (0.20 inch) But Less Than 10 mm (0.40 inch) |
1.5 mm (0.060 inch) |
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| Weld Face Width Over (10 mm)(0.40 inch) But Less Than 20 mm (0.80 inch) |
2 mm (0.080 inch) |
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| Weld Face Width Over 20 mm (0.80 inch) But Less Than 30 mm (1.20 inch) |
3 mm (0.120 inch) |
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| Weld Face Width 30 mm (1.20 inch) and Over |
4 mm (0.160 inch) |
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| Excess Weld Metal - Fillet Weld Convexity | 503 | Convexity Affects Weld Toe Angle, Reducing Fatigue Life | 90 Degrees |
| Weld Toe Angles of 135 Degrees and More Are Better | -- | ||
| Defect Limits Expressed as Minimum Toe Angles Allowed | -- | ||
| Excess Penetration | 5041, 5042, 5043 | Without Drawing Limitation | 2 mm (0.080 inch) (Any Length) |
| With "Melt - Thru" and "Flush" Weld Symbols | 1 mm (0.040 inch) (Any Length) |
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| With "Melt - Thru" and "Grind Flush" Symbols | Not Permitted (After Grinding) | ||
| Incorrect Weld Toe | 505 | When 1E2995 Applies (Expressed as a Toe Radius Rather Than a Toe Angle) | 3 mm (0.120 inch) Minimum Radius |
| Overlap | 5061, 5062 | Expressed as Minimum Toe Angle | 90 Degrees |
| Fillet Weld Leg Size - Undersize | -- | Applies to Either Weld Leg Measured Independent of the Other | -- |
| Maximum Undersize | 1 mm (0.040 inch) |
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| Maximum Length of Undersize Weld | 10% of Total Weld Length If At Least 10% of Total Weld Length is at Least 1 mm (0.040 inch) Over Nominal Size, Otherwise, No Undersize Length is Permitted |
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| Fillet Weld Leg Size - Oversize | -- | Applies to Either Weld Leg Measured Independent of the Other | -- |
| Maximum Oversize | +25% (max 3 mm (0.120 inch)) |
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| Conformance to Design - Fillet Weld Leg Sizes May be Oversized (Within Defect Limitations or Beyond) Without Correction Provided the Excess Does not Interfere with Satisfactory End Use of the Component ( Distortion, Fit-Up Interference) | -- | ||
| Fillet Weld - Linear Length when specified at less than the length of the joint | -- | Weld Size ≤ 6.5 mm (0.256 inch) |
± 6.5 mm (0.256 inch) |
| Weld Size ≥ 6.5 mm (0.256 inch) |
± 12.5 mm (0.492 inch) |
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| Fillet Weld Throat Size - Undersize | 5213 | Nominal Size (0.7 x Leg Size) Not Inclusive of Penetration Beyond the Weld Root | Not Permitted |
| Weld Crater Only - Maximum Undersize | 2 mm (0.080 inch) MAX - and Not to Exceed 20% of Specified Throat, Not Inclusive of Penetration Beyond the Weld Root (0.7 x Leg Size) |
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| Incompletely Filled Groove Weld | 511 | Careful Consideration Needs to be Given When Plate Mismatch is Apparent | Not Permitted |
| Weld Depth Must be Maintained as a Minimum | -- | ||
| Root Concavity on Open Root Groove Welds | 515, 5013 | Maximum Depth measured From Plate Surface or Tube Inner Surface - Any Length | 0.5 mm (0.020 inch) |
| Poor Restart (Tie - In) | 5171, 5172 | Measured in Terms of Excess Weld Metal (Fillet Weld Convexity) or Overlap on Groove Welds, Lack of Fusion, or Insufficient Throat | -- |
| Excess Weld Metal on Fillet Welds, Defect Limits Expressed as Minimum Toe Angles Allowed | 90 Degrees | ||
| Overlap on Groove Welds, Defect Limits Expressed as Minimum Toe Angles Allowed | 90 Degrees | ||
| Lack of Fusion - Visual Maximum Length Per Restart | 3 mm (0.120 inch) |
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| Insufficient Weld Throat | Not Permitted | ||
| Stray Arc Strike | 601 | -- | Not Permitted |
| Slag Residue | 615 | SMAW, SAW, FCAW, GMAW | Not Permitted |
| GTAW | Silicon Residue Permitted Unless Removal Specified by Drawing Note | ||
| Combined Discontinuities | -- | Total Maximum Combined Length of All Imperfections in a Weld, Expressed as a Percent of Total Weld Length | 15% |
| (No Single Type of Imperfection Can Exceed the Limits for That Single Type of Imperfection) | -- |
In order to verify the quality of the weld, refer to Figure 27 from Caterpillar Specification 1E99 which is shown above.
General Weld Repair
- Remove any components that prevent access to the cracked weld.
- Refer to ""Area Preparation" " Section in this Special Instruction.
- Use dye penetrant (PT) or magnetic particle (MT) in order to identify the extent and/or length of the necessary repair.
- Protect machined surfaces from sparks and weld debris.
- 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.
- Cracks in the weld and sound metal which are 50.8 mm (2.0 inch) beyond each end of the crack shall be removed by air carbon arc torch or grinder. Caution should 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 in order 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.
- Use PT or MT to inspect the gouged and ground area in order to ensure that the crack has been removed before welding commences.
- Repair the prepared groove utilizing the recommendations provided in the ""Welding Electrodes and Parameters" " Section in this Special Instruction.
- 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.
Inspection Procedure
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| Illustration 3 | g03353185 |
Typical view of RH side of the frame | |
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| Illustration 4 | g03351706 |
Typical view of LH side of the frame | |
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| Illustration 5 | g03351554 |
View of hairline crack at weld toe | |
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| Illustration 6 | g03351557 |
View of improper repair at weld toe | |
- Clean the area surrounding upper strut mount welds on the LH beam assembly, and the RH beam assembly.
- Perform a visual inspection on the four upper strut mount welds.
Note: Before proceeding, ensure that the cracks are completely through thickness. Cracks that do not propagate through the material thickness can be repaired from one side and will not require the disassembly and extent of repair for which this applies.
Removal of Machine Components
The following components require removal in order to complete either an RH or LH through thickness repair for the upper strut mount.
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| Illustration 7 | g03363157 |
View of the front RH of the truck | |
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| Illustration 8 | g03363159 |
View of the RH side of the truck | |
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| Illustration 9 | g03363160 |
View of the LH side of the truck | |
- Use an appropriate lifting device to remove the following components prior to performing the repair:
- Batteries (A) Refer to Disassembly and Assembly, (If located in the weld on platform).
- Exhaust group (B), Refer to Disassembly and Assembly
- Steering tank (C), Refer to Disassembly and Assembly
- Handrail group (D)
- RH bolt on platform (E) 107 kg (236 lb)
- RH (If equipped) and LH Front access ladder (F), Refer to Disassembly and Assembly in the Cab removal and install section.
- RH weld on platform (G) 131 kg (290 lb)
- LH fender (H), Refer to Disassembly and Assembly in the Cab removal and install section.
- LH Walkway (J), Refer to Disassembly and Assembly in the Cab removal and install section.
- Cab (K), Refer to Disassembly and Assembly in the Cab removal and install section.
- Batteries (A) Refer to Disassembly and Assembly, (If located in the weld on platform).
Note: Disassembly and Assembly, RENR8432 for information regarding the removal and installation of certain components.
Note: Disassembly and Assembly, RENR8434 for information regarding the removal and installation of certain components.
Note: Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tools Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.
- Disconnect any wiring harnesses under the RH platform group.
- Remove the welds that hold the weld on platform in place.
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| Illustration 10 | g03356429 |
- Attach a suitable lifting device to RH weld on platform group (A). The weight of RH platform group (A) is 131 kg (290 lb).
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| Illustration 11 | g03356427 |
- Remove RH weld on platform group (A) and retain mounting hardware.
RH Upper Strut Mount Procedure
Plate Removal for the RH Upper Strut Mount Weld Joint Repair
Note: Before proceeding, ensure that the cracks are completely through thickness. Cracks that do not propagate through the material thickness can be repaired from one side and will not require the disassembly and extent of repair for which this applies.
Note: Reference dimensions of all hardware should be recorded for reattachment later.
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| Illustration 12 | g03353185 |
Typical view of RH side of the frame | |
Note: To repair a through thickness crack, a section of the plate on top of the beam assembly will have to be removed. Removal of the plate will gain access to the inside of the beam. Once inside, the crack can be repaired inside and out and, then a new window plate can be installed on the top of the beam.
- Cut and remove a section of the top plate according to the dimensions shown in Illustration 14. The 6 mm (0.24 inch) internal plate (C) is welded internally to the top plate. Therefore, gouging or cutting will be required at that location to enable removal of the top plate. The internal plate will be damaged, so removal and reinstallation of a new plate will be required.
Note: The 965 mm (38 inch) is approximately 30 mm (1.18 inch) shy of the other 6 mm (0.24 inch) internal plate.
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| Illustration 13 | g03360018 |
(A) 995 mm (39.17 inch) (B) 517 mm (20.35 inch) (C) 6 mm (0.24 inch) Internal plates | |
Note: A section of the top plate will need to be removed. For guidance, Illustration 13 depicts the location of internal plates shown with the top plate removed. A cut will need to be made short of the internal plate as shown in Illustration 14. Remove any hardware on top of the plate that is affected by the removal of the section.
Note: Reference dimensions of all hardware should be recorded for reattachment later.
Note: Internally there are two plates (C) that are fillet welded to the top plate. The internal plate locations are shown in Illustration 13.
 | |
| Illustration 14 | g03360028 |
Typical top view of RH side of the frame (D) 965 mm (38 inch) | |
- Cut or gouge along the scribed lines in order to obtain separation of the top plate.
Note: The top plate is 6 mm (0.24 inch) thick and is attached on the sides with 6 mm (0.24 inch) fillet welds and at the casting end with a 6 mm (0.24 inch) J-Groove weld.
- After the top plate has been removed, gouge/cut and remove the damaged 6 mm (0.24 inch)internal plate (C) .
- The crack can now be excavated and ground out on the side plate and the bottom plate.
Removal, Preparation, Welding, and Finishing
 | |
| Illustration 15 | g02705621 |
Through thickness crack (M) Crack (N) Section thickness | |
 | |
| Illustration 16 | g03358544 |
Example of excavation in process (M) Crack (N) Section thickness (P) Gouged profile | |
 | |
| Illustration 17 | g02705698 |
Example of excavation extends through thickness (N) Section thickness (P) Gouged profile | |
- Remove or excavate defects by grinding or by arc air gouging. If arc air gouging is used, remove all slag and carbon residue by grinding.
- Finish grind to achieve a 70 degree included angle.
 | |
| Illustration 18 | g03358608 |
Example of prepared joint by grinding or sanding (N) Section thickness (R) Grind to profile of 70 degree angle | |
- Completely weld the prepared locations as shown above.
 | |
| Illustration 19 | g03358622 |
Example of welding completed from one side (N) Section thickness | |
 | |
| Illustration 20 | g03358625 |
Example of ensuring 100% fusion and penetration (N) Section thickness (S) Back gouge | |
 | |
| Illustration 21 | g03358694 |
Example of welding completed on opposite side (N) Section thickness | |
- Sand the welded areas flush on both sides as shown.
 | |
| Illustration 22 | g03358697 |
Example of excess weld reinforcement sanded flush on both sides (N) Section thickness | |
Note: Verify soundness of weld repairs via visual inspection (VT) and magnetic particle testing (MT) according to Acceptance Criteria – Welding
Installation of the New Internal Stiffener Plate
- Fabricate a new stiffener plate according to the Illustration shown.
Note: The new internal plate should be fabricated out of Material ASTM A572 Grade 42.
 | |
| Illustration 23 | g03358710 |
Internal Plate (A) 6 mm (0.23622 inch) (B) 112.78 mm (4.44015 inch) (C) 393.7 mm (15.49997 inch) | |
- Remove all previous welding debris from area where the internal plate had been attached.
- Tack and secure the new fabricated plate in place. Weld as shown in Illustration 25. Refer to Illustration 24 for location of the new internal plate.
 | |
| Illustration 24 | g03358992 |
View of the location of the internal plates (D) 6 mm (0.24 inch) (E) 995 mm (39.17 inch) (F) 517 mm (20.35 inch) | |
 | |
| Illustration 25 | g03358982 |
View of the necessary welds for the new internal plate (D) 6 mm (0.24 inch) | |
- Fabricate a steel backing strip that is approximately 25 mm (0.98 inch) wide by 6 mm (0.24 inch) thick by length required. The material can be mild steel such as ASTM A36. Grind to fit and insert as shown in Illustration 26 and tack weld in place.
 | |
| Illustration 26 | g03360037 |
Typical view of backing strip for RH rear area of upper strut mount | |
Window Plate Installation for the RH Upper Strut Mount Weld Joint Repair
- Fabricate a new RH window plate using the dimensions in Illustration 27. The new window plate should be made out of ASTM A572 Grade 42 or 50 6 mm (0.24 inch) thick. Grind a 45 degree bevel on the narrow end of the plate where the backing strip was attached previously.
 | |
| Illustration 27 | g03351885 |
RH window plate dimensions (U) 6 mm (0.24 inch) (V) 45 degree bevel (W) 494 mm (19.45 inch) (X) 339 mm (13.35 inch) (Y) 962 mm (37.87 inch) | |
- Locate the new plate as shown in Illustration 28.
 | |
| Illustration 28 | g03359081 |
View of the6 mm (0.24 inch) bevel groove weld (Z) 45 degree bevel (A) 3 mm (0.12 inch) | |
Note: The weld joint at the narrow end of the plate should be approximately as shown in Illustration 28.
- Tack weld the new plate into place.
- Weld the new plate alternating weld passes between each weld joint.
 | |
| Illustration 29 | g03351915 |
View of the window plate welding | |
- Sand excess weld metal (reinforcement) on single bevel groove weld flush with 6 mm (0.24 inch) plate, so that it does not appear as though a new window plate has been installed.
- Remove all weld spatter and inspect all welds ensuring conformance to the requirements specified in Acceptance Criteria.
- Reweld the upper strut mount ends with a continuous 8 mm (0.315 inch) fillet weld from bottom to top. Remove the remaining remnants of the factory fillet weld between points (A) and (B) and then reweld as shown in Illustration 30.
 | |
| Illustration 30 | g03351969 |
Note: Depending on the extent of the crack and repair, the external fillet weld around the upper strut mount ends will need to be rewelded. The weld needs to be a continuous 8 mm (0.315 inch) fillet weld from bottom to top. Remove the remaining remnants of the factory fillet weld between points (A) and (B) and then reweld as shown.
Note: To prevent recracking at the fillet weld toe on the upper strut mount, a postweld treatment will need to be applied.
- TTD (TIG Toe Dress) the weld toe of the 8 mm (0.31 inch) fillet weld as shown in Illustration 30. Refer to the Postweld treatment section to perform the TTD.
 | |
| Illustration 31 | g03351983 |
Note: TIG dressing will be downhill from point (B) to point (A) as opposed to the previous welding performed uphill from point (A) to point (B) .
Note: To prevent recracking at the fillet weld toe on the upper strut mount, a postweld treatment will need to be applied.
- After the post weld treatment has been performed, locate and reattach all hardware and platform.
LH Upper Strut Mount Procedure
Plate Removal for the LH Upper Strut Mount Weld Joint Repair
Note: Before proceeding, ensure that the cracks are completely through thickness. Cracks that do not propagate through the material thickness can be repaired from one side and will not require the disassembly and extent of repair for which this applies.
| | |
| Illustration 32 | g03351706 |
Typical view of LH side of the frame | |
Note: To repair this through thickness crack, a section of the plate on top of the beam assembly will have to be removed to gain access to the inside of the beam. Once inside, the crack can be repaired inside and out and, then a new window plate can be installed on the top of the beam.
- Cut and remove a section of the top plate according to the dimensions shown in Illustration 34.
Note: The 575 mm (22.64 inch) is approximately 30 mm (1.18 inch) shy of the 6 mm (0.24 inch) internal plate.
 | |
| Illustration 33 | g03356634 |
View of the internal plate location (top plate removed) (A) 6 mm (0.24 inch) Internal plates (B) 605 mm (23.82 inch) | |
Note: A section of the top plate will need to be removed. For guidance, Illustration 33 depicts the location of internal plate shown with the top plate removed. A cut will need to be made short of the internal plate as shown in Illustration 34. Remove and retain any hardware on top of the plate that is affected by the removal of the section.
Note: Reference dimensions of all hardware should be recorded for re-attachment later.
 | |
| Illustration 34 | g03356430 |
View of the location of the needed cut on the top plate (C) 575 mm (22.64 inch) | |
- Cut or gouge along the scribed lines in order to obtain separation of the top plate.
Note: The top plate is 6 mm (0.24 inch) thick and is attached on the sides with 6 mm (0.24 inch) fillet welds and at the casting end with a 6 mm (0.24 inch) J-Groove weld.
- After the top plate has been removed, gouge/cut and remove the damaged 6 mm (0.24 inch) internal plate (A) .
- The crack can now be excavated and ground out on the side plate and the bottom plate.
Note: Verify that all cracking has been removed via visual inspection (VT) and magnetic particle testing (MT) before the start of repair welding.
Removal, Preparation, Welding, and Finishing
| | |
| Illustration 35 | g02705621 |
Through thickness crack (M) Crack (N) Section thickness | |
| | |
| Illustration 36 | g03358544 |
Example of excavation in process (M) Crack (N) Section thickness (P) Gouged profile | |
| | |
| Illustration 37 | g02705698 |
Example of excavation extends through thickness (N) Section thickness (P) Gouged profile | |
- Remove or excavate defects by grinding or by arc air gouging. If arc air gouging is used, remove all slag and carbon residue by grinding.
- Finish grind to achieve a 70 degree included angle.
| | |
| Illustration 38 | g03358608 |
Example of prepared joint by grinding or sanding (N) Section thickness (R) Grind to profile of 70 degree angle | |
- Completely weld the prepared locations as shown above.
| | |
| Illustration 39 | g03358622 |
Example of welding completed from one side (N) Section thickness | |
| | |
| Illustration 40 | g03358625 |
Example of ensuring 100% fusion and penetration (N) Section thickness (S) Back gouge | |
| | |
| Illustration 41 | g03358694 |
Example of welding completed on opposite side (N) Section thickness | |
- Sand the welded areas flush on both sides as shown.
Note: Verify soundness of weld repairs via visual inspection (VT) and magnetic particle testing (MT) according to Acceptance Criteria – Welding
| | |
| Illustration 42 | g03358697 |
Example of excess weld reinforcement sanded flush on both sides (N) Section thickness | |
- Fabricate a steel backing strip that is approximately 25 mm (0.98 inch) wide by 6 mm (0.24 inch) thick by length required. The material can be mild steel such as ASTM A36. Grind to fit and insert as shown in Illustration 43 and tack weld in place.
 | |
| Illustration 43 | g03351873 |
Typical view of backing strip for RH rear area of upper strut mount | |
Note: Once repairs are complete, a new "additional" internal stiffener plate should be installed. Fabricate a new plate according to the dimensions shown in Illustration 44.
Installation of the New Internal Stiffener Plate
- Fabricate a new stiffener plate according to the Illustration shown.
Note: The new internal plate should be fabricated out of Material ASTM A572 Grade 42.
| | |
| Illustration 44 | g03358710 |
Internal Plate (A) 6 mm (0.23622 inch) (B) 112.78 mm (4.44015 inch) (C) 393.7 mm (15.49997 inch) | |
- Sand and clean base material where new plate will be installed.
- Tack and secure the new fabricated plate in place. Weld as shown in Illustration 45. Refer to Illustration 45 for location of the new internal plate.
 | |
| Illustration 45 | g03359210 |
View of the location of the new internal plate and weld information (D) New internal plate (E) 134 mm (5.28 inch) | |
Window Plate Installation for the LH Upper Strut Mount Weld Joint Repair
- Fabricate a new LH window plate using the dimensions in Illustration 46. The new window plate should be made out of ASTM A572 Grade 42 or 50 6 mm (0.24 inch) thick. Grind a 45 degree bevel on the narrow end of the plate where the backing strip was attached previously.
 | |
| Illustration 46 | g03359230 |
LH window plate dimensions (U) 796 mm (31.34 inch) (V) 45 degree bevel (W) 337 mm (13.27 inch) (X) 459 mm (18.07 inch) (Y) 572 mm (22.52 inch) | |
- Locate the new plate as shown in Illustration 48.
| | |
| Illustration 47 | g03359081 |
View of the6 mm (0.24 inch) bevel groove weld (Z) 45 degree bevel (A) 3 mm (0.12 inch) | |
Note: The weld joint at the narrow end of the plate should be approximately as shown in Illustration 47.
- Tack weld the new plate into place.
- Weld the new plate alternating weld passes between each weld joint.
 | |
| Illustration 48 | g03359256 |
View of the LH window plate welding | |
Note: Sand the weld on the left flush.
- Sand excess weld metal (reinforcement) on single bevel groove weld flush with 6 mm (0.24 inch) plate, so that it does not appear as though a new window plate has been installed.
- Remove all weld spatter and inspect all welds ensuring conformance to the requirements specified in Acceptance Criteria.
- Reweld the upper strut mount ends with a continuous 8 mm (0.315 inch) fillet weld from bottom to top. Remove the remaining remnants of the factory fillet weld between points (A) and (B) and then reweld as shown in Illustration 30.
| | |
| Illustration 49 | g03351969 |
Note: Depending on the extent of the crack and repair, the external fillet weld around the upper strut mount ends will need to be rewelded. The weld needs to be a continuous 8 mm (0.315 inch) fillet weld from bottom to top. Remove the remaining remnants of the factory fillet weld between points (A) and (B) and then reweld as shown.
Note: To prevent re-cracking at the fillet weld toe on the upper strut mount, a postweld treatment will need to be applied.
- TTD (TIG Toe Dress) the weld toe of the 8 mm (0.31 inch) fillet weld as shown in Illustration 30. Refer to the Postweld treatment section to perform the TTD on both ends of the upper strut mount.
| | |
| Illustration 50 | g03351983 |
Note: Depending on the extent of the crack and repair, the external fillet weld around the upper strut mount ends will need to be rewelded. The weld needs to be a continuous 8 mm (0.315 inch) fillet weld from bottom to top. Remove the remaining remnants of the factory fillet weld between points (A) and (B) and then reweld as shown.
Note: To prevent re-cracking at the fillet weld toe on the upper strut mount, a postweld treatment will need to be applied.
- After the post weld treatment has been performed, locate and reattach all hardware and platform.
Installation of Machine Components
| | |
| Illustration 51 | g03363157 |
View of the front RH of the truck | |
| | |
| Illustration 52 | g03363159 |
View of the RH side of the truck | |
| | |
| Illustration 53 | g03363160 |
View of the LH side of the truck | |
- Use an appropriate lifting device to install the following components after the repair is complete:
- Batteries (A) Refer to Disassembly and Assembly, (If located in the weld on platform).
- Exhaust group (B), Refer to Disassembly and Assembly
- Steering tank (C), Refer to Disassembly and Assembly
- Handrail group (D)
- RH bolt on platform (E) 107 kg (236 lb)
- RH (If Equipped) and LH Front access ladder (F), Refer to Disassembly and Assembly in the Cab removal and install section.
- RH weld on platform (G) 131 kg (290 lb)
- LH fender (H), Refer to Disassembly and Assembly in the Cab removal and install section.
- LH Walkway (J), Refer to Disassembly and Assembly in the Cab removal and install section.
- Cab (K), Refer to Disassembly and Assembly in the Cab removal and install section.
- Batteries (A) Refer to Disassembly and Assembly, (If located in the weld on platform).
Note: Disassembly and Assembly, RENR8432 for information regarding the removal installation of certain components.
Note: Disassembly and Assembly, RENR8434 for information regarding the removal installation of certain components.
Proactive Preventative Action
Note: For those trucks that did not have TIG dressing completed at the factory, it can be done prior to cracking to ensure a longer fatigue life at this location. Refer to the Post weld TIG treatment for complete details.
- TTD (TIG Toe Dress) the weld toe of the factory 8 mm (0.31 inch) fillet weld on both ends of the upper strut mount.
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| Illustration 54 | g03361066 |
View of typical factory fillet weld around the end of the upper strut mount plate. | |
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| Illustration 55 | g03361076 |
View of factory 8 mm (0.31 inch) fillet weld after TIG dressing. | |
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| Illustration 56 | g03361083 |
Close up view of the TTD (A) TTD (TIG Toe Dress) (B) 8 mm (0.31 inch) Fillet weld (C) Upper strut mount | |
Note: TTD (TIG Toe Dress) will be performed downhill from point B to point A on both ends of the upper strut mount.
- Clean and inspect radius for conformance.
- Inspect all welds to ensure conformance to requirements specified in Acceptance Criteria (Welding).
Post weld TIG Treatment of Fillet Welds for Improved Fatigue Life
Note: The fatigue performance is controlled by the profile of the weld toe. The fatigue performance applies to fabricated structures that have fillet welded attachments to highly stressed members. The fatigue performance can be improved by altering the original welded toe profile. Altering the original welded toe can be achieved by using several post weld treatment options. The following procedure describes a method of using an electric arc to reduce adverse profiles and stress risers. The following method creates a seamless transition from one component to the next component.
| Required Equipment | |
|---|---|
| Tool | Description |
| GTAW (TIG) Power supply and a torch. | The power supply must be able to produce 200 amps (min. 60% duty cycle) with a hand control or a foot control. |
| Shielding Gas | 100% Argon and flow meter |
| Electrode | Lanthanated or Ceriated or Thoriated Tungsten 2.4 mm (0.09 inch diameter) If needed: ER70S-2 filler metal 1.5 mm (0.06 inch diameter) |
| Grinder | Pneumatic or electric with carbon steel wire wheel attachment |
| Grinding Wheel | Aluminum Oxide |
| Radius gauges | |
- Cleanliness and tungsten electrode preparation are the first steps in order to ensure that a proper TIG dressing is achieved. Remove all contaminants thoroughly from the fillet weld and the surrounding base metal. All rust, dirt, oil, scale, and silicate islands must be removed, via a grinder with a carbon steel wire attachment.
 | |
| Illustration 57 | g01989379 |
2.4 mm (0.09 inch) Tungsten Electrode Preparation (M) Striations or Grinding Marks | |
- Prepare a 2.4 mm (0.09 inch) tungsten electrode. Refer to the dimensions that are shown in Illustration 57. The striations should run parallel to each other.
- Adjust the shielding gas flow rate to 15 CFH. Adjust the current control to approximately 200 amps. If a ramp down control is present on the power source, utilize the ramp down control to ensure that proper crater fill control is achieved.
- A number of different techniques exist for TIG dressing due to the variation of the contour of the fillet weld toe. The contour of the fillet weld toe must be reshaped. Use a stringer or weave manipulation of the torch in order to achieve a smooth radius of the weld. A minimum radius of 5.0 mm (0.20 inch) must exist between the base material and the weld metal.
- Illustration 58 represents the stringer technique of welding. The center of the arc needs to be 0.0 - 2.0 mm (0.0 - 0.08 inch) from the weld toe into the base material.
 | |
| Illustration 58 | g01989420 |
Stringer Technique | |
Note: Use a 10 to 15 degree push angle for the stringer technique.
- Illustration 59 represents the weave technique of welding.
 | |
| Illustration 59 | g01989494 |
Weave Technique | |
Note: Use a 10 to 15 degree push angle for the weave technique.
- Illustration 60 represents a cross section view of a proper TIG dressed fillet weld.
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| Illustration 60 | g01989613 |
- Illustration 61 and Illustration 62 demonstrate the expected results.
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| Illustration 61 | g01990055 |
 | |
| Illustration 62 | g01990056 |
- Once TIG dressing is completed, the area needs to be cleaned and painted in order to prevent pitting due to corrosion.
Note: Poorly shaped fillet welds with 70 degree to 90 degree transition angles will require several overlapping TIG dressing runs. Overlapping of the TIG dressing runs is required in order to stabilize the weld toe transition area.
Note: TIG dressing can be conducted in the vertical position as long as the TIG dressing is performed in a downhill progression.
Note: Some undercuts will require the addition of filler metal. Adding filler metal can be accomplished by hand feeding ER70S-2 1.5 mm (0.06 inch diameter) into the weld pool. You then repeat the TIG dressing in order to achieve the desired toe radius and the desired profile.