Procedure for Water-Cooled Welding of Track Rollers {0679, 4180, 7950} Caterpillar


Procedure for Water-Cooled Welding of Track Rollers {0679, 4180, 7950}

Usage:

D6D 01Y
Caterpillar Products
Machines with Grease Lubricated Track with Swage
Machines with Greased Lubricated Track (GLT)
Machines with Positive Pin Retention (PPR) Track
Machines with Positive Pin Retention 2 (PPR2) Track
Machines with Rotating Bushing Track
Machines with Sealed Positive Pin Retention (PPR) Track
Machines with Sealed Track
Machines with Sleeve Bearing Track
Machines with SystemOne Undercarriage
Machines with non-PPR Sealed and Lubricated Track
Track Drills
MD5150C (S/N: SEY1-UP)

Introduction

Table 1
Revision  Summary of Changes in SEBF8507 
18–21  Added serial number prefixes for New Product Introduction. 
17  Added serial number prefixes for New Product Introduction.
Updated introduction information. 
16  Added serial number prefixes for New Product Introduction. 

© 2019 Caterpillar All Rights Reserved. This guideline is for the use of Caterpillar dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law. Information contained in this document is considered Caterpillar: Confidential Yellow.

This Undercarriage Reconditioning Bulletin 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 Undercarriage Reconditioning Bulletin must be used with the latest technical information that is available from Caterpillar.

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Summary

This bulletin covers water-cooled welding of track rollers. Track roller preparation, welding steps, and bearing inspection are also covered.

Safety



Illustration 1g02139237

Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.

This bulletin may contain hazardous steps. A safety alert symbol like the one below is used to indicate a hazard.

Warning messages identify a specific, imminent, latent, hazard that has a reasonable probability of resulting in personal injury or death if the warning is ignored.



Illustration 2g03186216
Example warning

------ WARNING! ------

Do not attempt to disassemble or assemble this machine until you read and understand the disassembly and assembly instructions. Improper disassembly and assembly procedures could result in injury or death.


------ WARNING! ------

Inspect all threaded components before use. Damaged threads may fail under hydraulic pressure. Broken threads may release flying objects that are propelled with great force. Personal injury or death can occur if struck by flying objects.


------ WARNING! ------

Do not stand near the hydraulic press while the press is in operation. A component that slips or breaks under pressure may fly into the air with great force. Personal injury or death can occur if struck by flying objects.


Canceled Part Numbers and Replaced Part Numbers

This document may not include all 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.

Track Roller Preparation

The following recommendations apply to track roller preparation:


NOTICE

Do not weld (or rebuild) track rollers that have less than 70% tread wear. Do not weld track rollers that have more than 110% tread wear. If either roller tread surface is outside this range, the roller should not be rebuilt.


Reference: Refer toSpecial Instruction, PEKP9400, "Custom Track Service Handbook" for measurement instructions and wear specifications.

  1. Remove the rollers from the machine.

  2. Clean the track rollers with high-pressure water or steam to remove large pieces of mud and packed in dirt.


    Illustration 3g02441316
    Use an air powered wire brush for further cleaning.

  3. After the pressure washing, clean the roller tread surface and flanges using an air powered wire brush. Refer to Illustration 3. Rust and moisture must be removed from the roller surface. Surface contaminants, such as rust and moisture can cause hydrogen embrittlement and possible fracture of the track roller during weld buildup. Cleaning will contribute to the quality of the welding, since less dirt and oil get into the flux.

    Note: During cold weather, the rollers must be at room temperature before welding is started. The recommended temperature range is 16° to 21° C (60° to 70° F).

  4. Visually inspect the flange and tread area of track rollers and bolt holes for evidence of crackling. If cracks are suspected but cannot be easily seen, use a magnetic particle or dye penetrant inspection technique. If cracks are found, do not weld the rollers.


    Illustration 4g02441338

  5. Remove any metal rolled-over at the inner edge of the treads before welding any single flange roller. Refer to Illustration 4.


    Illustration 5g02441356

  6. Elevated sprocket tractors have deeper wear limits on the track rollers. This deeper wear pattern must be trimmed. Trim the rolled-over material further back from the edge and downward toward the roller hub. Refer to Illustration 5.

    Note: Trimming is necessary to prevent cracks from lengthening into the weld deposit.


    NOTICE

    When trimming the rolled-over material using a cutting torch, trim smoothly and uniformly to prevent notching. Notches can be a source of roller cracking.


  7. Use a grinder to smooth the rough areas after trimming.

Preparation of Track Rollers -Low Sprocket Tractors



    Illustration 6g02441359

  1. Remove the roller shaft oil plug and the end collars, then inspect the Duo-Cone seals. Refer to Illustration 6. Refer to Undercarriage Reconditioning Bulletin, SEBF8511, "Reusability Recommendations for Duo-Cone Seals" for inspection instructions.


    NOTICE

    Duo-Cone seals must be kept in matched pairs.


  2. Loose dirt should be removed from the end collars, but hard packed dirt should not be disturbed.

  3. Check bearing-to-shaft clearance with the 0.64 mm (0.025 inch) wire of the FT1412 gauge. Acceptable clearance ranges from 1.26 mm (0.050 inch) down to 0.64 mm (0.025 inch). This clearance is needed to prevent shaft seizure after welding.

  4. The 0.64 mm (0.025 inch) wire should be inserted into the area between the shaft and bearing, at the top, to a depth of 50.8 mm (2.00 inch) to check the minimum clearance the entire length of the bushing.

    1. If clearance is less than 0.64 mm (0.025 inch), disassemble the roller and resize the bushing.

    2. If the 1.26 mm (0.050 inch) wire can be inserted between the shaft and the bearing indicating that the clearance is more than 1.26 mm, replace the bushing.

      Note: Try to have resized exchange bushings available to speed up the rebuilding process. Usually re-sizing is required only at the time of the first rebuild. Subsequent rebuild clearance is generallygreater than the minimum clearance.



    Illustration 7g02441361

  5. Inspect the roller components to prepare for assembly. Check the end collars for cracks. If the roller shaft was removed, make sure that the roller shaft is clean and oil passages are free of dirt and obstructions. The bushings should be clean and dry. Lubricate the bushing bore, O-ring seal, and thrust face before assembly. See Illustration 7.


    Illustration 8g02441376

  6. Install the Duo-Cone seals after the shaft and bushings have been assembled. Correct Duo-Cone seal installation is critical for the long life of a roller. See Bulletin MP7, SEBF8511-01 for detailed instructions. Lubricating the toric ring may cause leakage during welding. The end collars should be wired or banded to prevent internal pressure from forcing the end collars away from the shaft on roller groups. See Illustration 8.


    Illustration 9g02441378
    External water probe. Check the probe seal and shaft prior to each use.

  7. Set up the water supply. If the welding machine uses an external water probe, check the probe seal and shaft prior to each use. See Illustration 9. A damaged water seal or loose shaft can restrict water circulation inside the roller. The resulting heat buildup can damage internal roller components. Install the water probe, water hoses and turn on the water. If a leak develops, rotate the shaft inside the roller to seat the seals. A continuous leak is usually from damaged or omitted seals, or Duo-Cone seals that are defective. The leak check should be made before the roller is placed in the welder to prevent water from leaking into the flux supply.

Preparation of Track Rollers -Elevated Sprocket Tractors

Elevated Sprocket machine track rollers must be disassembled and a cooling adapter installed to permit water-cooled welding. Resizing of the track roller bushings is done after the rollers are welded.



    Illustration 10g02441379
    CP9361 Air Scribe Tool

  1. Remove hardened dirt and debris from around the roller retainer bolt heads. The use of a pneumatic scribing tool quickly and safely removes this dirt and debris using high vibration and air pressure. See Illustration 10.


    Illustration 11g02441383
    Remove the retainers from the rollers


    Illustration 12g02441397
    Remove the duo-Cone seal (inner) from the rollers


    Illustration 13g02441398
    Remove the roller shaft from the rollers

  2. Remove the track roller retainers, the Duo-Cone seal (inner), and the roller shaft from the rollers. See Illustrations 1011,12, and 13.

    Table 2
    Model  D11T
    D11R
    D11N
    D10T
    D10R
    D10N
    D10
    D9L 
    D9T
    D9N
    D9R
    D8T
    D8N
    D8R
    D8L
    D8
    D7R
    D7H
    D7E
    D7 
    973
    963
    953
    943
    D6T
    D6R
    D6N
    D6M
    D6H
    D6K
    D6
    D5N
    D5M
    D5H
    D4H
    D4 
    Cooling Adapter  6V-6140  6V-6163  1U-5530 
    End Plate  6V-7048
    6V-7049 
    6V-7053  1U-5532
    1U-5531 
    End Plate Seals  8F-8733
    8F-9516 
    5F-3106  2J-8163
    5H-6734 
    Bearing Housing Assembly  6V-7055  6V-7054  1U-5533 
    Adapter Shaft Assembly  6V-7056  6V-7056  1U-5534 
    Quick Disconnect Couplings 1  5V-8610
    5V-8611 
    5V-8610
    5V-8611 
    5V-8610
    5V-8611 
    Thrust Washers  9N-1545  9N-1545  9J-0114 
    Shaft Seal  2H-3933  2H-3933  3H-2652 
    Retainer Ring  9H-5604  9H-5604  7H-4574 
    Adapter Seals  8F-8733
    8F-9516 
    5F-3106  2J-8163
    5H-6734 

    1The quick disconnect coupling must be used for the cooling adapters.

    Note: There are three cooling adapters used during welding. The components are given in table 2.



    Illustration 14g02441419

  3. The quick disconnect couplings shown in Illustration 14 are not a part of the cooling adapter and must be ordered separately. The Caterpillar part numbers for the quick disconnect couplings are 5V-8610 and 5V-8611. It is recommended that these larger couplings be used to replace the smaller fittings in all the water and air lines of the welding machines and other water probes or adapters.


    Illustration 15g02441418

  4. To assemble the cooling adapter, select the correct side of the housing for the side of roller to be welded. See Illustration 15.

  5. Assemble a thrust washer and the shaft O-ring seal to the adapter shaft. See Illustration 14. Lubricate the shaft and bearing with a multipurpose grease. Using a twisting motion, press the shaft into the bearing housing.


    Illustration 16g02441437

  6. Install the second thrust washer, retainer springs, and the O-ring seal in the flange of the bearing housing as shown in Illustration 16. Check the water inlet tube and water return hole. A loose tube or a restriction in the tube or return hole can result in an overheated roller. Connect the quick disconnect coupling so the incoming water is directed to the water inlet tube.

    Note: Adapters should be disassembled, cleaned, and lubricated periodically.



    Illustration 17g02441438

  7. Fasten the end plate to the roller using three bolts. See Illustration 17. The retainer faces of the track roller must be clean to ensure a good O-ring seal on both sides of the roller.


    Illustration 18g02441439

  8. Fasten the adapter to the opposite side of the roller with three bolts. See Illustration 18. (Adapter is pictured with couplings).

  9. Prior to placing the roller in the welder, assemble the water connections and check for leaks. The most probable cause of leaks would be a damaged or omitted O-ring seal.


    Illustration 19g02441440

  10. Place the roller in the welder and make sure that the holding devices are secure and in correct alignment. Recheck the roller for water leaks. Do not drive the roller with a block tack-welded to the flange. Doing so could result in a stress riser which could cause cracking. The adapters are driven by the FT-1738 Stud. See Illustration 19.

Flange Welding Procedure

Total rebuild (welding) of flange and treads may be cost prohibitive and can result in future cracking.

Do not rebuild any track roller flanges unless necessary. Consider cost and refer to the following criteria to determine if flange welding should be done.


NOTICE

It is important that flange welding occurs before roller tread welding.


  1. Preheat the flange to a temperature of 204° C (400° F). The preheating will dissipate any grease, water, or oil on the flanges.

    Note: Heat will be distributed evenly into the tread and roller when welding flanges first. Welding flanges first normalizes thermal stress.



    Illustration 20g02441458

  2. Refer to illustration 20 and table 3 for minimum rebuild criteria.

    Note: Refer to "Flange Welding Parameters" for welding equipment.

    Table 3
    Flange Welding Measurements 
    To Weld a Roller Flange On:  X Must Be Less than: 
    D11N
    D11R
    D11T 
    20.7 mm (0.81 inch) 
    D10N
    D10R
    D10T 
    14.7 mm (0.58 inch) 
    D10  22.24 mm (0.876 inch) 
    D9N
    D9R
    D9T 
    13.0 mm (0.51 inch) 
    D9L  13.7 mm (0.54 inch) 
    D9  14.22 mm (0.560 inch) 
    D8N
    D8R
    D8T 
    13.0 mm (0.51 inch) 
    D8L  11.01 mm (0.433 inch) 
    D8  12.7 mm (0.50 inch) 
    D7E
    D7H
    D7R 
    13.0 mm (0.51 inch) 
    D7  9.7 mm (0.38 inch) 
    D6
    D6K
    D6H
    D6M
    D6N
    D6R
    D6T 
    10.0 mm (0.39 inch) 
    D5
    D5H
    D5M
    D5N 
    9.0 mm (0.35 inch) 
    D4
    D4H 
    8.0 mm (0.31 inch) 


    Illustration 21g02441476
    Welding is to be initiated at the radius between the tread and flange.

  3. Welding should be initiated in the radius between the tread and flange using a stringer bead. Refer to Illustration 21.

  4. After flange welding is complete, be prepared to continue with tread welding. Go to the section titled "Tread Welding Procedure".

Flange Welding Parameters

Use the following welding parameters for rebuilding track roller flanges:

Table 4
Wire Type 
Parameters  Stoody 205 HD  Stoody 105, 105B  Lincore 40 
Flux  Stoody Rollrite HD  Stoody Rollrite  Lincoln 880 
Amps  400  350  350 
Volts  30  26  26 
Wire Speed Feed  95 ipm  43 ipm  62 ipm 
Stickout  31.75 mm (1.250 inch)  31.75 mm (1.250 inch)  31.75 mm (1.250 inch) 
Polarity  Reverse  Reverse  Reverse 
Rotation  30-35 ipm  30-35 ipm  30-35 ipm 

Note: To avoid weld failures, use only the recommended combinations of submerged arc weld fluxes and wires.



Illustration 22g02441496

Wire feed speed is related to amperage and is a more precise means of controlling weld deposition rates. The Lincoln Electric portable wire feed speed meter, Model No. K283, can be used to measure the speed of the wire being pulled by the drive motors. See Illustration 22.

Lincoln Electric portable wire feed speed meter, Model No. K283

Wire feed speed measurement is required for machine setup.

Tread Welding Procedure


    NOTICE

    It is important that flange welding be done before roller tread welding.


  1. Check the general condition of the roller welding machine and make sure that all functions are in good working order.


    Illustration 23g02441498

  2. Replace any worn welding tips. A welding tip is considered unusable when the hole is worn to an oval shape 50% larger in width than the diameter of the welding wire. Worn welding tips will allow the wire to whip during weld buildup, causing poor weld appearance. See Illustration 23.

  3. Use the proper wire and flux combination to assure a good weld appearance. Small pieces of slag should be filtered out of the flux used for submerged arc welding. New flux should be blended with old flux to provide a proper flux which can be used with hardfacing wire to obtain a desired hardness and chemistry. Do not use more than 25% recycled flux. Do not use reground flux as reground flux contributes to cracking. It is more cost efficient to use new flux than to replace a cracked roller.

    Note: When using Stoody 205 HD wire, Rollrite HD flux, the slag produced cannot be reground. The economics of regrinding and flux properties do not warrant reuse.

  4. Prepare the roller for welding.

    1. Flange welded: If flange welding is performed, weld the roller treads immediately after the flanges. Rollers should be at 204° C (400.0° F)

    2. Flange not welded: Rollers should be preheated to a temperature of approximately 204° C (400.0° F). Preheating will remove any condensation and surface contaminants and reduce thermal shock to the roller. Preheating will take 3 to 5 minutes to heat a cool roller to this temperature. Leave off the water pump during this time to allow the roller to warmup faster and retain the heat.

  5. Use a fire-resistant material to retain the flux on the roller tread. Welding a stringer bead on the inside edge of single flange rollers is not recommended since this can result in roller cracking.


    Illustration 24g02441499
    Weld head in correct position above roller

  6. Place the welding head about 6.4 mm (0.25 inch) ahead of top dead center. Adjust the lead as necessary to obtain the proper bead, but never put the welding head behind top dead center. See Illustration 24.


    Illustration 25g02441519

  7. Position the tip of the welding torch approximately 31.75 mm (1.250 inch) above the roller tread. See Illustration 25. The current being conducted through the exposed wire will preheat the wire and permit an increase in deposition from electrical stickout. Raise the tip as needed to maintain this distance from the roller tread. Once the arc is initiated, be sure to turn the water pump back on.

  8. Apply a 25.4 mm (1.00 inch) wide oscillating pass in the center of treads using an oscillating speed of 75-80 inches per minute with .200 in. index. Oscillating speed is set by oscillating the welding tip in 1 inch strokes per minute. Index is set by roller rotation in inches per oscillation. These settings should be made prior to starting the welding.

  9. When the weld is initiated, adjust the electrical controls for proper weld parameters.

    Adjust the electrical controls for weld parameters. Refer to table 5.

    Table 5
    Stoody 205 HD  103 ipm wire feed speed
    450 amps (30 V) 
    Stoody 105 or 105B  52 ipm wire feed speed
    375 amps (28 V) 
    Lincore 40  107 ipm wire feed speed
    475 amps (28 V) 

  10. When the roller has rotated to the starting point of the weld, increase the width of the pass. Reduce the oscillating speed to 50-55 inches per minute.


    Illustration 26g02441520

    Note: The tread surface of most rollers will be worn concave. See Illustration 26.

  11. Use partial width welding passages to fill in the lower areas of the tread surface to level it. This permits the weld material to feather into the parent material. Do not use dwell (hesitation) during this fill-in process, even if the tread is worn flat. Begin with at least one narrow weld pass to warmup the roller.


    Illustration 27g02441521


    Illustration 28g02441522

  12. Build the tread surface up to a finished diameter. Use dwell to get good tie-in of the tread surface to the flanges. Dwell provides a radius between the tread and flange to reduce the chances of inclusions and stress risers. See Illustration 27 and Illustration 28.


    NOTICE

    Do not weld any stringer beads on the tread surface. This is the main cause of cracking hard core rollers welded by the water-cooled process.


  13. Once the tread welding has started, do not stop until the tread is built up to the finished diameter. The Handbook, PEKP9400, "Custom Track Service" provides roller tread diameters for reference of buildup.

Tread Welding Parameters

The following welding parameters are recommended for rebuilding track rollers.

Table 6
Consumables 
Type of Wire 
Parameters  Stoody 205 HD  Stoody105
Stoody 105B 
Lincore 40  Welding Alloys P-S 
Flux  Stoody Rollrite HD  Stoody Rollrite  Lincoln 880  Stoody Rollrite 
Wire Feed Rate  103/95 ipm1  52 ipm  107/70 ipm1  100/73 ipm1 
Amperage  450/4001  375  475/3751  450/4001 
Volts  30  28  28  28 
Polarity  Reverse  Reverse  Reverse  Reverse 
Deposition Rate  16.1 lb/hr
15.3 lb/hr1 
9.5 lb/hr  14.0 lb/hr
10.4 lb/hr 
16.1 lb/hr
15.3 lb/hr1 
Deposition Efficiency  .94  .9  .87  .92 
Flux to Wire Ratio  .6 lb  1.12 lb  .80 lb  .65 lb 

1Smaller Rollers (D7 and smaller) must be rebuilt at reduced welding parameters to avoid problems with weld pool control and slag removal.

Note: To avoid weld failures, use only the recommended combinations of submerged arc weld fluxes and wires.

The following Consumable Arc Time Comparison Track Rollers Chart can be used to compare welding times. The four columns show the welding times for rebuilding a 100% worn roller using the products and the recommended welding parameters listed in Illustration 6. No flange welding was included in the times.

Table 7
Consumable Hour Ranges 
Roller Size & Part No.  Stoody 105 or 105B  Lincore 40  Stoody205 HD 
D11N
D11R
D11T 
4.03 to 4.73  2.73 to 3.21  2.52 to 2.97 
D10N
D10R
D10T 
3.42 to 4.00  2.32 to 2.71  2.15 to 2.51 
D10  2.25 to 3.33  1.53 to 2.26  1.41 to 2.09 
D9N
D9R
D9T 
2.93 to 3.55  1.99 to 2.41  1.84 to 2.23 
D9L  2.13 to 2.82  1.45 to 1.91  1.34 to 1.77 
D9  1.36  0.92  0.84 
D8N
D8R
D8T 
2.12 to 2.46  1.44 to 1.67  1.33 to 1.55 
D8L  1.59 to 2.21  1.08 to 1.50  1.00 to 1.39 
D8  1.09  0.74  0.68 
983  1.07  0.73  0.67 
D7E
D7H
D7R 
1.01  0.92  0.66 
D7  0.67  0.62  0.44 
D6
D6K
D6H
D6M
D6N
D6R
D6T 
0.57 to 0.88  0.52 to 0.81  0.38 to 0.58 
D5
D5H
D5M
D5N 
0.42 to 0.66  0.39 to 0.61  0.28 to 0.44 
D4
D4H 
0.30 to 0.42  0.28 to 0.38  0.20 to 0.28 
973  0.68 to 1.14  0.62 to 1.04  0.45 to 0.75 
963  0.56 to 0.96  0.51 to 0.88  0.37 to 0.63 
953  0.44 to 0.75  0.40 to 0.69  0.29 to .050 
943  0.33 to 0.52  0.30 to 0.48  0.22 to 0.34 

The two most important factors which influence bead development when welding in the oscillating mode is lead and oscillating speed. Lead is the distance ahead of the roller centerline at which the weld deposit is made. Oscillating speed determines bead size. The faster the speed, the narrower the bead. Extra factors which influence bead contour are arc voltage, amperage, and spindle index. Voltage determines the width and shape of the bead. Amperage (wire feed speed) determines the rate of deposition and penetration. The spindle index determines the thickness of the weld deposit.

See Illustration 29 and table 8 for various kinds of beads that can be produced by the oscillating technique. By observing the bead patterns and making the adjustments indicated, the various improper bead forms can be corrected.



Illustration 29g02441556

Table 8
Bead  Cause/Result  Remedy 
Bead A
(Puddle Effect) 
Incorrect  The lead is either too far behind the roller centerline (top dead center) or the oscillating speed is too low.  Correct the lead and/or the oscillating speed. 
Bead B
(Lazy Eight) 
Incorrect  The gap between the beads is caused by the spindle index being too high. The gap between the beads indicates little or no dwell. The stretched eight-shaped pattern indicates that the oscillation speed is too high.  Correct the spindle index and/or dwell amount. Also consider working with oscillation speed. 
Bead C
(Little Dwell) 
Incorrect  Too little or no dwell on the flange side and too much metal running over the inner edge.  The use of fire-resistant material to form a flux dam is especially important for the inside edge of single flange rollers. 
Bead D
(No Dwell) 
Incorrect  Dwell-less bead with too much index.  The index should be reduced so beads will overlap better. 
Bead E
(Wrong Lead) 
Incorrect  Distortion caused by improper lead plus excessive dwell on the outside flange.  By reducing the left hand dwell, the excess buildup can be eliminated. Properly adjusting the lead will eliminate the wave like effect found in the rest of the bead. 
Bead F represents a correctly oscillated welding bead. 

Post Welding Procedure

Slow cooling will allow stresses to normalize and allow any entrapped hydrogen to diffuse to the surface through the weld material.

Use the following information to make sure that the track rollers are rebuilt with maximum quality.

  1. After water circulation is discontinued, use high-pressure air to force the waste water through the water adapter.

  2. Allow rollers to cool.

    Note: To prevent rapid cooling in colder climates, the welded rollers can be placed in an insulated box or a container filled with the used submerged arc welding flux.

    Note: The rollers can also be covered with a fire retardant blanket right after welding to slow down the cooling process.


    NOTICE

    Allow the roller to cool slowly. Do not set roller on a concrete floor or near a draft of air.


  3. Lubricate and store rollers:

    1. Low Sprocket Tractor Rollers: After cooling to room temperature, these rollers should be filled with lubricating oil and dipped in a protective coating until ready for use.

    2. Elevated Sprocket Rollers: If roller bushing-to-shaft clearance is within specifications, reassemble rollers, fill with lubricating oil, and dip in protective coating.

Note: The wire on the end collars should be left on during storage to prevent end collar separation during handling.

Note: To prevent possible cracking of welded rollers during cold weather, store rebuilt rollers in a heated storage area.

Welding Highlights

  1. Both track roller treads must be worn between 70 and 110%. The track roller flanges must meet the dimensions given in this bulletin.

  2. Rollers should be at a minimum temperature of 16° C (60.8° F) before starting to preheat for welding.

  3. Clean all the weld surfaces including the flanges. Use a wire brush or an 8T-3054 Metal Reconditioning Disc and an air powered tool to clean the flanges.

  4. Remove the cold-flow rolled material from the single flange rollers. Make a smooth and even cut at a 45º angle. Trim behind any fractured areas and trim down toward the roller hub. Check for cracks in the trimmed areas, around the bolt holes and in the existing weld surfaces. Dress the cut with a grinder to remove all rough areas and all excess slag and carbon. Be careful not to notch the roller with the grinder.

  5. Do not tack weld anything on the roller.

  6. Install the proper water adapter on the roller, and mount both the roller and the water adapter on the welding machine.

  7. If the flanges are to be welded, preheat the flanges to 204° C (400° F). Weld the flanges before welding the treads. Start the arc in the radius between the flange and the tread.

  8. Preheat the treads 204° C (400° F) to remove moisture and other contaminants and to warm the surface area of the roller.

  9. Use the proper combination of welding wire and flux. Use clean flux. Filter the flux to remove slag, and do not use more than 25% recycled flux.

  10. Weld with the wire at positive polarity (reverse).

  11. Check the machine parameters for the correct wire feed speed amperage, voltage, oscillation speed, and indexing.

  12. Do not use stringer beads on the treads.

  13. The first weld pass should be approximately 25.4 mm (1.00 inch) wide and at 75 ipm to 80 ipm oscillating speed.

  14. All weld layers should meet the flange with a smooth radius

  15. Do not stop welding until the roller is rebuilt.

  16. Allow the roller to cool slowly. Do not set roller on the concrete floor or where there is a draft.

  17. Rebuild the roller to the 0% wear limit. Do not weld the roller oversize.

Roller Bushing Resizing

Track roller bushings on Low Sprocket Tractors must be resized if the bushing-to-shaft clearance before welding is less than 0.64 mm (0.025 inch).

On track rollers of Elevated Sprocket Tractors bushing-to-shaft clearance are checked after the rollers are welded with the cooling adapters. Install the roller shaft and insert a 0.46 mm (0.018 inch) wire at the top between the shaft and the bushing. If the clearance is less than 0.46 mm (0.018 inch), the roller bushing must be resized to prevent shaft seizure.

A bearing burnishing procedure has been developed which increases the bushing diameter to correct the distortion created during welding. This procedure and tooling are presented in Bulletin, SEBF8586, "Removal, Installation, and Conditioning of Idler Bearings and Track Roller Bearings".

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