- 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
- Machines with Greased Lubricated Track (GLT)
- Track Drills
- MD5150C (S/N: SEY1-UP)
Introduction
Revision | Summary of Changes in SEBF8506 |
21 | Added serial number prefixes for New Product Introduction. |
20 | Added serial number prefixes for New Product Introduction. |
19 | Added serial number prefixes for New Product Introduction. |
18 | 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.
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.
Summary
Idler and roller rebuilding is a profitable operation that provides the dealer and the customer a viable rebuild option at a reasonable expense. This rebuild procedure allows for the idler or roller to be resurfaced to the original dimensions. Provide for equivalent wear rates as a new idler or roller. The instructions given in this guideline provide the necessary information to evaluate and rebuild an idler or roller. Considerations have been taken to improve rebuild efficiency and increase wear life. Necessary tooling is listed throughout the procedure.
References
Media Number | Title |
SEBF8599 | Undercarriage Reconditioning Bulletin , "Conventional (Dry) Welding Procedure for Rollers and Idlers" |
SEBF8571 | Undercarriage Reconditioning Bulletin , "Reconditioning Dimensions for Idlers" |
SEBF8585 | Undercarriage Reconditioning Bulletin , "Disassembly and Assembly Procedures for Idlers with Conventional Duo-Cone Seals" |
SEBF8582 | Undercarriage Reconditioning Bulletin , "Disassembly and Assembly Procedures for Idlers with Inverted Duo-Cone Seals" |
SEBF8586 | Undercarriage Reconditioning Bulletin , "Removal, Installation, and Conditioning of Idler Bearings and Track Roller Bearings" |
SEBF8509 | Undercarriage Reconditioning Bulletin , "Welding Wire and Flux" |
PEKP9400 | Service Handbook , "Custom Track Service Handbook" |
SEBF8552 | Undercarriage Reconditioning Bulletin , "Idler Weld Rebuild Procedure" |
Safety
Illustration 1 | g02139237 |
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.
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 Society2501 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 LaborWashington, D.C. 20210 |
Canceled Part Numbers and Replaced Part Numbers
This document does not include all canceled part number and replaced part number information. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.
Note: The true center line must be kept on all idler rebuild procedures. All idler width dimensions are based off center line of the idler. Measure from machined retainer surface on hub to establish the true center line of hub.
Preparation
Illustration 2 | g02352954 |
Trimming roller using a torch |
Clean the surface and flanges of rollers and idlers to remove rust, oil, water, and dirt to avoid porosity, hydrogen embrittlement, and unsound welds.
Determine if the edge of the single flange roller is rolled over at the inside on the tread area. Trim away any rollover with a torch or grind before starting the weld. Refer to Illustration 2. Trimming the roller will prevent spalling from cracks in the fatigued metal. The rollers and idlers should be inspected for abnormal wear. Flat places or thin spots should be built up before completely building up to the desired diameter. Some idlers which have been subjected to extreme conditions may develop cracks at or near the base of the flange. These cracks should be welded before rebuilding. A more ductile wire should be used to insure a quality weld. Be sure to follow correct preheating procedures before manually welding the idler.
After the roller or idler has been cleaned, remove the plug and drain the oil. Disassemble the roller or idler clean the internal components and the roller assembly or idler assembly.
Set Up
Illustration 3 | g02353376 |
Weld head in correct position above roller. (A) Approx. (1) Flux holder (2) Flux tube (3) Welding head (4) Roller |
After disassembly, mount the roller or idler in the automatic welder and preheat if necessary. Establish the center line of the roller or idler . Position the wire
Illustration 4 | g02353416 |
Weld head in correct position above idler. (B) Approx. (1) Flux holder (2) Flux tube (3) Welding head (5) Idler |
For idlers, position the wire
Illustration 5 | g02353417 |
Lead affects weld bead shape (6) Proper bead (7) Too far off center (8) Too close to center |
If the wire is too close to center, the molten metal will peak and may even spill, resulting in an unsatisfactory surface. Refer to Illustration 4.
If the wire is too far off center, a concave bead will be formed, sometimes with center line cracking.
Flux control plays an important part in shaping the weld bead. To produce a good quality weld deposit, properly support the granular flux with a non-burning flux holder between the flux tube and the roller or idler surface. The depth of the flux can best be established by slowly decreasing the flux control lever until the welding action is submerged. The gases will puff up around the welding wire and sometimes burn. The flux must not be disturbed in or about the welding zone.
Preheat
Welding procedures should be followed which will slightly preheat the roller before the highly stressed edges are welded. Usually this procedure provides satisfactory results but when all the original hardness is not worn away, preheating to
If the welding is done in cold ambient air, remove the “chill” from the roller. The temperature of the roller should be at least
When rebuilding fabricated type idlers, the surface to be rebuilt should be preheated only when necessary to bring the temperature up to approximately
Illustration 6 | g02353418 |
Drill or cut hole in the side of fabricated type idlers before welding |
NOTICE |
---|
Always drill or cut a hole in the side of fabricated type idlers to vent and relieve pressure that forms inside the idler. This pressure, caused by condensed water being heated by the welding process, can cause the idler to explode. |
Fabricated idlers should be preheated to
General Procedures Build-Up and Hard-Surfacing
Illustration 7 | g02353419 |
Build up low area with partial pass (9) Third Hard Surface Pass (10) Second Hard Surface Pass (11) First Hard Surface Pass (12) Double flange roller (13) Partial pass buildup material |
On rollers or idlers that are worn concave, the low area should be filled with a partial pass of the build-up material using a uniform stepover (partial overlapping of successive weld beads). Another method would be to vary the stepover and/or travel speed. A small stepover for areas which are concave. Larger stepover where the contour of the roller does not require a large amount of metal. A reduction in travel speed will also deposit more metal per linear inch. After the low surfaces have been restored evenly, complete hard surfacing passes should be applied to build the component up to the desired diameter. Refer to Illustration 7.
To minimize bore shrinkage, the roller is kept away from excessive heating by minimizing the heat input. Table provides typically used weld speed, amperage, and voltage values for a given component. Allow the rollers to cool between passes. General sequence when surfacing a set of rollers with the thin wall bushings pressed into the roller, the temperature at the bushing must not exceed
Suggested Travel Speeds, Amperage, and Voltage | |||
Track Roller Welding - Dry | |||
Model | Rotation Speed (in/min) | Amperage | Volts |
D10 | 30 to 35 | 325 to 350 | 28 |
D9 | 30 to 35 | 375 to 400 | 30 |
983 | 30 to 35 | 300 to 325 | 28 |
D8 | 30 to 35 | 375 to 400 | 30 |
D7 | 30 to 35 | 350 to 375 | 30 |
D6 | 35 to 40 | 325 to 350 | 28 |
D5 | 35 to 40 | 325 to 350 | 28 |
D4 | 35 to 40 | 300 to 325 | 28 |
D3 | 35 to 40 | 300 to 325 | 26 |
Carrier Roller Welding | |||
Model | Rotation Speed (in/min) | Amperage | Volts |
D9 | 30 to 35 | 350 to 375 | 30 |
D8 | 30 to 35 | 325 to 350 | 28 |
D7 | 30 to 35 | 325 to 350 | 28 |
D6 | 35 to 40 | 325 to 350 | 28 |
D5 | 35 to 40 | 325 to 350 | 28 |
D4 | 35 to 45 | 300 to 325 | 26 |
D3 | 35 to 45 | 300 to 325 | 26 |
Idler Welding | |||
Model | Rotation Speed (in/min) | Amperage | Volts |
D11 | 30 to 35 | 375 to 425 | 28 |
D10 | 30 to 35 | 375 to 425 | 28 |
D9 | 30 to 35 | 375 to 425 | 28 |
D8 | 30 to 35 | 375 to 425 | 28 |
D7 | 30 to 35 | 375 to 425 | 28 |
D6 | 35 to 40 | 375 to 425 | 28 |
D5 | 35 to 40 | 325 to 375 | 28 |
D4 | 35 to 40 | 325 to 375 | 28 |
D3 | 35 to 40 | 325 to 375 | 28 |
A template and large calipers used as a gauge aid in restoring rollers and idlers to original dimensions.
Note: The true center line must be kept on all idler rebuild procedures. All idler width dimensions are based off center line of the idler. Measure from machined retainer surface on hub to establish the true center line of hub.
A stepover of 1/3 to 1/2 the bead width every revolution finishes with a smooth surface.
When the roller flanges are hard surfaced, the roller axis may be positioned 5 degrees to 45 degrees from the horizontal.
Illustration 8 | g02353420 |
Roller flange build-up (3) Welding head (4) Roller |
Move the head
Illustration 9 | g02353421 |
Idler edge beads (14) Improper bead (15) Proper edge bead |
Illustration 10 | g02353422 |
Idler edge bead build-up (16) Idler flange (17) Build up on edge first |
Rebuilding the edge of the idler to size by laying successive beads one on top the other before stepping over is an advantage. It is difficult to hold the molten metal and flux on the edge if the idler is too hot from welding the tread area. Refer to Illustration 8 and Illustration 9.
Welding should be started at the edge of the idler and continue into the base of the flange.
When the idler flanges are hard-surfaced, the idler can be placed either in a horizontal position or tilted 20 degrees from the vertical. The surface of the idler acts as a flux support when placed in these positions.
Note: The true center line must be kept on all idler rebuild procedures. All idler width dimensions are based off center line of the idler. Measure from machined retainer surface on hub to establish the true center line of hub.
Travel Speed
Travel speed affects the penetration and bead width. If the travel speed is doubled, the penetration and bead width is reduced to about half. Penetration is reduced because the same amount of wire is spread over a greater length of work.
Lead
Illustration 11 | g02353423 |
Correct lead will give the proper bead (A) Approx. (2) Flux feed tube (6) Proper bead |
Note: First bead on roller will be oval or convex at proper distance setting.
Lead plays an important part in submerged arc welding on cylindrical work and compares closely with rod position in manual welding. On cylindrical work, the arc is about 1 inch ahead of top center to give the molten flux an opportunity to form the desired bead. The one basic requirement is that the molten metal must at least partially solidify before the molten metal passes top center. Refer to Illustration 11.
Lead is an adjustment that must be understood by an operator. Voltage, current, or travel speed adjustments should not be used to overcome a faulty lead adjustment. Bead shape will demonstrate to the operator whether the lead is correct or not.
Illustration 12 | g02353424 |
Too far off center (18) Bead high oval (19) Bead irregular along edge (20) Bead flat-may hair crack down center or concave |
Illustration 13 | g02353636 |
Too close to center (21) Bead with knots (22) Bead with narrow raised places |
Too much lead causes a wide, flat bead that may even be depressed in the center. If the lead is huge, the ripples will reverse and indicate a metal overrun. If the lead is too short, the ripples are long, the bead is high and rough with extra weld overrun. Correct lead gives a smooth, slightly crowned bead with about 30 degree lines or ripples. For examples of improper weld beads due to wrong lead, refer to Illustration12 and Illustration 13.
Cooling
Upon completion of the welding cycle, the rollers or idler should be removed from the machine and allowed to cool slowly.
It is important to “Slow Cool Down” the roller or idler after the roller or idler has been surfaced. Proper cooling method can be accomplished by placing the roller or idler in a “Slow Cool Down” box. The roller or idler should remain in the insulated box until safe to handle by hand. The roller or idler should not be placed near drafts and should never be placed on the floor in the vertical position. Potential rim cracking could occur.
After the fabricated idler has cooled, plug weld the hole on the side.