PRODUCT SUPPORT PROGRAM FOR REWORKING THE LIFT ARM LIFT CYLINDER BOSS WELD ON CERTAIN 424 II BACKHOE LOADERS Caterpillar

PRODUCT SUPPORT PROGRAM FOR REWORKING THE LIFT ARM LIFT CYLINDER BOSS WELD ON CERTAIN 424 II BACKHOE LOADERS

Usage:

TEBE1770-00

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21Jul2014

D-384

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*After Failure Only*	PRODUCT SUPPORT PROGRAM FOR REWORKING THE LIFT ARM LIFT CYLINDER BOSS WELD ON CERTAIN 424 II BACKHOE LOADERS
6119 6118		PS52719

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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 "PS52719" 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.

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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.

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TERMINATION DATE

31Jul2016

PROBLEM

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The existing boss that the lift arm lift cylinder attaches to at the main frame may crack at the weld on certain 424 II Backhoe Loaders. If the existing boss weld cracks, it will need to be reworked.

AFFECTED PRODUCT

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Model	Identification Number
424 II	JRC06400-06481, 6483, 6485-6486, 6488-6682, 6685-7319, 7330-7399, 7402-7403, 7409-7427, 7432-7436

PARTS NEEDED

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No parts needed for this program

ACTION REQUIRED

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Refer to the attached Rework Procedure.

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SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
0-5000 hrs, 0-24 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%

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NOTE: This is a 12.0-hour job
Note: After completion of the weld repair, enter the frame serial number in the claim story for warranty approval.

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PARTS DISPOSITION

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Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Rework Procedure

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This Rework Procedure covers the repair welding method of main frame lift cylinder mounting boss weld crack at field. Refer to Image1.1.1.

Image1.1.1

REWORK PROCEDURE:

1. Park the machine in a level ground.

2. Place the bucket parallel to the ground and keep the front axle tire touching on the ground. Place the stabilizer in such a way that it just touches the ground. Refer to Image1.2.1.

Image1.2.1

3. Turn off the engine.

4. Relieve the pressure in cylinders by moving the levers in all direction. Refer to the Disassembly and Assembly, "System Pressure - Release", for additional information.

5. Remove either the diesel tank/battery box from the crack observed side. Refer to Image1.3.1.

Image1.3.1

6. Remove the lift cylinder along with hoses and pins and secure the hydraulic ports to avoid any foreign particle entry. Install a dummy plug at the tube from which disconnects the lift cylinder hose.

7. Remove the negative battery cable at the battery.

8. Clamp the ground cable to the component that will be welded. Place the clamp as close as possible to the weld. Make sure that the electrical path from the ground cable to the component does not go through any bearing/cylinder. This is to avoid arcing issue.

9. Protect any wiring harnesses from the weld debris.

10. Before doing the rework the weld process need to be identified for rework - MMAW/SMAW or GMAW.

11. Preferable do the rework with GMAW weld process. If the facility is not available, go with MMAW/SMAW weld process with specified diameter electrode.

12. The person/operator who is going to do rework in the field should be qualified in 4F position since this is a circumferential weld involving 2F, 3F, and 4F position welding.

13. Remove the weld crack by grinding all around the circumference.

14. Keep the rework surface free from moisture and dust.

15. Inset the dummy pin (same diameter of lift cylinder pin) in the boss, with grease, before welding in order to avoid distortion.

16. Follow the welding sequence shown in Image1.4.1.

a) Root pass to fill the excess fit-up gap.
b) First pass on the pivot boss side.
c) Second pass on the plate side.
d) Make sure that final fillet size of 12mm is achieved.
e) Remove slag after each weld run.

Image1.4.1

f) Smooth merging by grinding and sandering. Refer to Image1.5.1.

Image1.5.1

Image1.6.1

g) Check for visual weld defect inspection. The weld shall be free from cracks, porosity, undercut, and incomplete fusion. Refer to Image1.7.1.

h) Check with "Dye Penetrant Test" to ensure surface soundness of the weld joint as per procedure explained at the end.

Image1.7.1

17. Paint the welded area with a pressurized spray can or by brush. Be sure to mask the pivot bore with dummy pin. Refer to Image1.8.1.

Image1.8.1

18. Reassemble the cylinder, pin, and hoses. Remove the dummy pin.

19. Connect all hydraulic lines to their respective ports and ensure no leaks after starting the engine.

20. Repeat the same process for the other side pivot boss, even if failure is NOT observed.

MMAW/SMAW Process:

a. Electrode: AWS A5.1 E7018 Advani/ESAB electrode
b. Polarity - AC ? DCEP
c. Electrode Dia ? 3.15/4.0 mm
d. Current ? 100 ? 145 A/150-190 A
e. Electrode should be baked at temperature range as per the manufacture recommendations.
f. Waving should be avoided during welding.
g. Adopt back step 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.

GMAW Process:

a. Electrode: AWS A5.18 E70S6 Hyundai/ESAB electrode
b. Polarity - AC ? DCEP
c. Electrode Dia ? 1.2 mm
d. Current ? 170 -300 A / Voltage ? 23-29 V
e. Waving should be avoided during welding.

DYE PENETRANT TEST:

Dye penetrant testing is a 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 MAKE:
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:

a. Remove any loose scale and dirt by wiping. Remove oils and coatings using solvents or grinding.

b. Wipe the area to inspect with a solvent dampened cloth to remove remaining dirt and allow the area to dry.

c. Apply penetrant by spraying to the entire area to be examined.

d. Allow 10 to 15 minutes for penetrant to soak.

e. After the penetrant has been allowed to dwell, remove most of the excess penetrant
with clean, dry wipes.

f. The last traces of penetrant should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.

g. 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 ? 15 minutes before inspecting for surface discontinuities.

h. The developer will act to draw entrapped penetrant out of the discontinuity. A red stain on the developer indicates a possible surface discontinuity.

i. Clean the area of application of the developer with solvent cleaner. If any cracks are located, rework the area by removing the crack with grinding. 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.