Usage:
29Mar2016 |
After Failure Only | PRODUCT SUPPORT PROGRAM FOR REPAIRING CRACKED REAR FRAME SLIDING RAIL ASSEMBLY ON CERTAIN 424 AND 424B BACKHOE LOADERS |
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7054 | PS53179 |
NOTE: | Caterpillar’s obligations under this Service Letter are subject to, and shall not apply in contravention of, the laws, rules, regulations, directives, ordinances, orders, or statutes of the United States, or of any other applicable jurisdiction, without recourse or liability with respect to Caterpillar. |
NOTE: | This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS53179" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code. |
NOTE: | The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst. |
TERMINATION DATE |
31Mar2018 |
PROBLEM
It has been observed that crack may develop on the rear frame sliding rail assembly, during certain extreme applications, on the part numbers listed below (as applicable), on certain 424 and 424B Backhoe Loaders. Part Number (Frame Assembly) -- Group Number (Loader Frame Group) 372-3390 -- 420-1112 306-7885 -- 332-7493 329-4941 -- 329-4942 324-5969 -- 324-5970 |
AFFECTED PRODUCT
Model | Identification Number |
424 II | JRC06400, 6460, 6463, 6468-6470, 6472, 6481-6485, 6487, 6490, 6493-6682, 6685-7319, 7330-7368, 7370-7809 |
424B | JRN01000-01100, 1102-3117, 3119-3150 |
424B HD | JRY01000-01289 |
PARTS NEEDED
Qty |
Part Number | Description |
3 | 9R1706 | RAIL |
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer. |
ACTION REQUIRED
A crack on the single side or both sides should be weld repaired on both sides. Replacement of parts other than those listed in the Parts Needed not covered under this Service Letter program. Note: Prior approval from the Service Tech Representative, at the dealership, is required in order to complete this service letter program. Note: This Service Letter program can only be completed once for a particular machine serial number, within the defined machines listed in the affected product, when a crack failure has been identified on the rear frame sliding rail. |
Image1 |
Image2 |
SERVICE CLAIM ALLOWANCES
0-24 mo |
||||||
25-36 mo |
NOTE: This is a 20.0-hour job | ||||||
Note: This Service letter is for completing an after failure (crack) repair and is not to be used for covering cost associated with the normal maintenance / inspecting the frame assembly either by visual inspection or ultra sound inspection. |
PARTS DISPOSITION
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling. |
Problem Description: A crack may develop at the machine frame rear sliding rail plate bottom or top. In case of crack found on either side, the following repair procedure has to be carried out. An example of the area prone for a crack is shown in Image1.1.1 and 1.1.2. |
Image1.1.1 |
Image1.1.2 |
Safety Procedures to be Followed: 1. Park the machine on a level surface. If you must park on a grade, chock the machine. 2. Apply the service brake in order to stop the machine. Move the transmission control lever to the NEUTRAL position. 3. Move the speed control lever to the LOW IDLE position. 4. Engage the parking brake. 5. Engage the transmission neutral lock. 6. Lower all work tools to the ground. 7. Stop the engine using engine shut-off cable. 8. Release the hydraulic system pressure and follow instructions before removal of cylinders and hoses. Refer to the Operation and Maintenance Manual, for your machine, for additional information. 9. Turn the engine start switch to OFF position and remove the key. |
Rework Procedure: The following is the procedure to repair a crack at rail assembly bottom or top. The repair procedure consists of weld repair and inspection. Do not perform any of the procedures until you have read all the information in this publication. For disassembly and assembly instructions, refer to your machine's Service Manual, Parts Manual, and Operation and Maintenance Manual. Parts Needed: |
Image1.3.1 |
Consumables Required for Repair: |
Image1.4.1 |
Safety Warnings and Notices: |
Image1.5.1 |
Image1.5.2 |
Image1.5.3 |
Image1.5.4 |
Image1.5.5 |
Image1.5.6 |
Image1.5.7 |
Preliminary: WELDER QUALIFICATION / SAFETY: 1. Welder must be qualified for right process SMAW and all welders must be qualified for fillet and groove welding in 3G and 4G as outlined in the current ANSI/AWS standards D1.1, or D14.3. 2. The welding operator must also have used the welding process during the last six months or be re-certified for this purpose before welding. 3. Welding quality is critical to the success of the installation procedure. Welds must be smooth and continuous. Visual aspect, undercuts, overlaps, shape irregularities, excess of penetration is critical for the structure fatigue life. Welds must be smooth continuous. Grind the ends of the welds to a smooth radius. 4. Personal protection should be provided. Weld fumes and gases can be dangerous to health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill. ELECTRODE / CHARACTERISTICS: The Manual Metal Arc Welding (MMAW/SMAW) process shall be used with E7018 welding electrode. The weld deposited by these electrodes will have the following minimum mechanical properties. TENSILE STRENGTH: 480 MPa YIELD STRENGTH: 400 Mpa ELONGATION: 22% - Use completely dry electrodes. - All electrodes must be dried. The electrode should be baked / dried at temperature range as per the manufacture recommendations or can be dried by heating the electrodes to 300 degrees Celsius (572 degrees Fahrenheit). The electrodes must be dried for at least 30 minutes. - Remove from the oven, at a time, electrodes that are sufficient for ten minutes of welding only. - Polarity ? Use the direct current electrode positive (DC reverse polarity) polarity. - The weld pass volume shall not exceed two times the electrode diameter. - Adopt backstep method or strike the arc on a small steel plate prepared for this particular purpose, because arc striking on base metal is in danger of initiating cracking. - Use stringer bead and very short arc. - Remove slag after every pass using wire brush. For more information about stick welding SMAW, refer to SEBD0512, Reuse And Salvage Guidelines, "Caterpillar Service Welding Guide". ELECTRODE DIAMETER AND CURRENT SETTINGS FOR WELDING: DIAMETER / LENGTH / CURRENT IN AMPS: 3.15mm 450 mm 110 - 130 4.0 mm 450 mm 150 ? 190 PARTS TO BE REMOVED: Disconnect and remove all digger hydraulic hose assemblies and plug all machine valve assembly ports to prevent dirt entry. Remove all machine structures (slide frame assembly along with swing frame, boom assembly, stick assembly, bucket, linkages, along with all rear structure cylinders). Drain and ensure no oil inside valve compartment and cover the valve area to prevent from damage/dust entry. Disconnect electrical connections near to the slide frame to avoid any damage during repair. Disconnect the battery connection. REPAIR PROCEDURE: 1. Clean the area to be reworked. Ensure that the area is free from oil, grease, paint, and dirt. |
Image1.6.1 |
Image1.6.2 |
2. Gouge out and remove cracked rail plate to the length of 25mm more on each side. Refer to Image1.7.1. Ensure that there is no damage to the inner box stiffener during the removal process of the cracked rail. Refer to Image1.7.2. 3. Add a 12 x 45 degree chamfer on both edges of the rail. Refer to Image1.7.1. |
Image1.7.1 |
Image1.7.2 |
4. Cut the 9R-1706 Rail (procured separately) to the required length and make a 12 x 45 degree chamfer. Refer to Image1.8.1. |
Image1.8.1 |
5. Locate the new processed rail plate into the removed portion of the cracked rail, such that it should be flush with top and bottom faces and flat within 0.5mm for rail front face. Tack weld the plate with rail assembly and ensures the flatness is maintained. Preheat the welding area to 150 degrees Celsius (maintain an interpass temperature of 150 - 175 degrees Celsius maximum, if multipass welding is used, and complete the weld as shown in Image1.9.1. Grind the weld smooth to make the welded plate flat with the rail assembly. |
Image1.9.1 |
6. Trim 20mm of rail height at the bottom portion of bottom rail assembly and 20mm height at the top face of the top rail assembly. Refer to Image1.10.1. |
Image1.10.1 |
7. Make a 12 x 45 degree chamfer at the bottom rail assembly and top rail assembly. Refer to Image1.11.1. |
Image1.11.1 |
8. Trim 9R-1706 Rail 2 to the length of 2004mm and add a chamber. Refer to Image1.12.1. |
Image1.12.1 |
9. Centralize the above rail plate over the reworked face of rear rail assembly (top and bottom rail), aligning the faces as shown in Images1.14.2 and 1.14.3. Use proper clamps to maintain flatness of 0.5mm. Ensure a 770 +/- 1.5 vertical dimension is maintained between rail plates outer. Refer to Image1.14.1. |
WELD PROCEDURE: 1. Clean the area to be welded, free from oil, grease, paint, and dirt. Attach the welding ground cable directly to the rear rail assembly nearer to the welding area. 2. Protect all machined surfaces from sparks or spatter produced by the welding, chipping, and/or grinding operations. 3. Ensure proper stiffeners/clamps are provided to welding to avoid distortion. Preheat all weld joints to 100 degrees Celsius (maintain an interpass temperature of 150 Degrees Celsius maximum, if multipass welding is used). 4. Weld the top and bottom rail assembly. Refer to Images1.14.2 and 1.14.3 |
Image1.14.1 |
Image1.14.2 |
Image1.14.3 |
5. Clean and remove the metal burrs from the repaired area. Use suitable grinding/finishing equipment to smooth the surface of the built up area to the original profile (matching with the adjacent area weld profile) check for visual weld defect inspection, if anything noticed grind the defective location and re=weld the defect location. Check that the reworked area is free from external defects and check with DP test for defect free welding. |
INSPECTION: The weld shall be free from cracks, porosity, undercut, and incomplete fusion. All weld quality shall conform to ANSI/AWS D1.1 or D14.3 or Caterpillar Engineering Specification 1E0099. DYE PENETRANT TEST: Dye penetrant testing is non-destructive testing method for detecting discontinuities open to the surface such as cracks, seams, laps, surface weld flaws, etc. MATERIALS REQUIRED: SPRAY TYPE. ORION: CLEANER: This removes dirt before dye application and dissolves the penetrant making it possible to wipe the surface clean. PENETRANT: This solution is highly visible, and will seep into openings at the surface of a part by means of capillary action. DEVELOPER: This provides a blotting action, bringing the penetrant out of the discontinuities and providing a contrasting background to increase the visibility of the penetrant indications. PROCEDURE: 1. Remove any loose scale and dirt by wiping. Remove oils and coatings using solvents or grinding. 2. Wipe the area to inspect with a solvent dampened cloth to remove remaining dirt and allow the area to dry. 3. Apply penetrant by spraying to the entire area to be examined. 4. Allow 10 to 15 minutes for penetrant to soak. 5. After the penetrant has been allowed to dwell, remove most of the excess penetrant with clean, dry wipes. The last traces of penetrant should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly. 6. Apply an even, thin layer of developer over the area being inspected. A few very thin layers are a better application method than one thicker layer. Allow the developer to dry completely for 10 to 15 minutes before inspecting for surface discontinuities. 7. The developer will act to draw entrapped penetrant out of the discontinuity. A red stain on the developer indicates a possible surface discontinuity. 8. Clean the area of application of the developer with solvent cleaner. If any cracks are located, rework the area by removing the crack with gouging method or grinding. Cracks must be completely removed to sound metal prior to welding. Verify that the crack has been completely removed by following the steps detailed in dye penetration inspection method. Repair the area using a qualified welder. Clean and inspect the weld repair. The weld shall be free from cracks, porosity, undercut and incomplete fusion. Paint the area as needed. 9. Reassemble all the rear structures and cylinders to the reworked rear rail assembly 10. Connect all hydraulic lines to respective ports of machines valve and ensure no leak. 11. Connect the battery line. 12. Check and ensure the hydraulic system pressure as per recommendation. 13. Ensure the smooth movement of the slide frame assembly over rear rail assembly. |