Repair of Web Cracks In Final Drive Planetary Carriers {4092} Caterpillar

Earthmoving Compactor

All

Off-Highway Truck/Tractor

All

Wheel Dozer

All

Wheel Loader

All

Introduction

© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.

This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.

For technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

Canceled Part Numbers and Replaced Part Numbers

This document may include canceled part numbers and replaced part numbers. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Important Safety Information

Illustration 1	g02139237

Follow all safety warnings. Most accidents that involve product operation, maintenance, or repair are caused by failure to observe safety warnings. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. Personnel must be properly trained to perform maintenance, repair, or operate any machine. Safety precautions and warnings are provided this instruction and on Caterpillar products. These warnings should be observed before performing any procedures. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The warnings in this publication and on the product are not all inclusive.

The hazards are identified by the “Safety Alert Symbol” which is followed by a “Signal Word” such as “DANGER”, “WARNING” or “CAUTION”. The “WARNING” Safety Alert Symbol is shown in Illustration 2.

Illustration 2	g00008666

This safety alert symbol means:

Pay Attention!

Become Alert!

Your Safety is Involved.

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

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

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. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.

Summary

Some wheel loader and tractor final drive planetary carriers may crack at the inner and outer deck separator webs after some time period. The repair procedures in this guideline provide a method to salvage an otherwise usable component to minimize owning and operating costs.

Crack/Surface Preparation

1. Use an electric or pneumatic grinder with a carbide cutter to remove the crack as shown in Illustration 3 through Illustration 5. Round off the edges and corners of the cut to avoid stress points. Do not use a grinding wheel. The abrasive grains can embed into the surface and interfere with weld fusion.
   Show/hide table

   Illustration 3	g02271233
   Crack in the web area (1) Typical crack location

   Show/hide table

   Illustration 4	g02271234
   Web area after the crack has been removed. (2) Rounded corners

   Show/hide table

   Illustration 5	g02271235

2. Inspect the area visually to make sure that the crack has been removed.

3. Clean all oil, grease, paint, dye penetrant, and so on, from the area affected by heat. Remove surface oxides from the area that is to be repaired.

   Note: Good cleaning and surface preparation is important, if a good quality repair is to be made.

Preheat

Preheating or postheating of the area for repair is not required. For this welding procedure, the carriers should be at room temperature, approximately 20 °C (68 °F), and must be protected from all drafts, especially in cold weather.

Welding Instructions

Show/hide table

Personal injury or death can result from fumes, gases and ultraviolet rays from the weld arc. Welding can cause fumes, burn skin and produce ultraviolet rays. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing area. Wear eye, ear and body protection before working. 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 cause death. Read and understand the manufacturer's instructions and your employer's safety practices. Do not touch live electrical parts. See "American National Standard Z49.1, Safety in Welding and Cutting" published by the American Welding Society. American Welding Society 2501 N.W. 7th Street Miami, Florida 33125 See "OSHA Safety and Health Standards, 29 CFR 1910", available from U.S. Department of Labor. U.S. Department of Labor Washington, D.C. 20210

Note: Be sure the surface to be welded has been correctly cleaned and prepared for the repair procedure. Refer to the topic, "Crack/Surface Preparation", in this guideline. After completing the preparation, use the procedure that follows.

1. Put a 1U-6339 Polarity Tester on the carrier, and touch the welding electrode to the metal disc to check the polarity of the welding machine. See Illustration 4. The LED readout will indicate negative (-) for straight polarity or positive (+) for reverse polarity.
   Show/hide table

   Illustration 6	g02271335

   Note: Straight polarity allows for shallow penetration, less heat input, and increased weld deposit. Reverse polarity has greater heat input, more penetration, and more dilution of the base material. When welding cast iron, make sure that the correct polarity for the weld material being used to get the desired results.

2. Mask the planetary shaft bores and thrust faces to protect from weld spatter.

   1. Stick Electrode: Set the welding machine for DC straight [negative (-)] polarity and 45 amps. (Verify the current setting by doing welding on a piece of scrap.) Use 1U-5379 Weld Rod, 2.0 mm (0.08 inch) diameter. The weld deposit must not be more than twice the diameter of the electrode core, 4.0 mm (0.15 inch) diameter.

   2. Wire: Use 1.14 mm (0.045 inch) diameter, Inco 44 wire from Inco Alloys International. Set the power supply to 18V DC (reverse polarity) and short arc mode. Set the wire feed to 6096 mm/min. (240 ipm). Current reading will be approximately 125 amps. Use 75/25 Argon/CO2 shield gas at a flow of 1.12 m³hr (40 cfh).
   Show/hide table

   Illustration 7	g02271393
   Direction of weld passes (3) Top deck (4) Web (5) Weld pass 1 (6) Weld pass 3 (either direction) (7) Weld pass 2 (8) Bottom deck

3. Begin the weld bead at one end of the groove as shown in Illustration 7. Do not weld more than 25 mm (0.1 inch) at one time. Immediately after making each weld pass, use a powered single or multiple needle descaler and thoroughly peen the weld.
   Show/hide table

   NOTICE
   DO NOT USE ANY TYPE OF DYE PENETRANT INSPECTION PROCEDURE DURING THESE INTERMEDIATE INSPECTIONS. The penetrant will cause weld contamination.

4. Inspect each pass for cracks or porosity.

   Use an electric or pneumatic grinder wit a carbide cutter to remove any cracks or open porosity pockets. Weld over this area and repeat the peening and inspection process.

   Note: At the end of each weld pass, always pull the arc back over the weld deposit before breaking the arc to reduce the possibility of crater cracking. Always strike the arc on the weld deposit - never on the base metal.

5. Allow each weld pass to cool to 43 °C (109.4 °F). Weld a bead of 25.0 mm (0.98 inch) or less at the other end of the groove and peen the weld immediately.

6. Continue the weld -peen -cool cycle and work toward center of the groove. Refer to Illustration 7 and Illustration 8.
   Show/hide table

   Illustration 8	g02276755
   Pattern for weld passes

7. Continue this process until the groove has been filled. Use the electric or pneumatic grinder to blend the weld with the casting profile. Peen the area after shaping the weld to reduce the stresses induced by the grinding tool.

8. Use a dye penetrant to inspect for cracks and porosity.

   Note: Do not use a magnetic particle inspection system. The weld fusion zone will always indicate a crack even when there is none.