Reusability Guidelines and Installation Procedures for Split Master Links {4170, 4176} Caterpillar

Caterpillar Products

Machines with Positive Pin Retention (PPR) Track

Machines with Rotating Bushing Track

Machines with Sleeve Bearing Track

Machines with non-PPR Sealed and Lubricated Track

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

Master links and master bolts are the most sensitive components of the track link assembly. When track type machines are in operation, there is a load concentration in the master links and bolts. Several factors can contribute to master link failure. Master link failure will cause track separation. Factors that contribute to master link failure are listed below.

• The condition of contact surfaces between heads of the master bolts and the master shoes.

• The condition of mating surfaces of the master shoes and master links and the link halves.

• The condition of the threads in the link halves and on the master bolts.

• The tightening torque used on the master bolts.

Note: When a link assembly is brought into the shop for scheduled repair or reconditioning, some components will have small cracks and abrasion. The abrasion and cracks cannot be seen during disassembly. A careful inspection of each component is essential. Use a magnifying glass, dye penetrant, or magnetic particle tester to aid in the inspection.

References

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 identify 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.

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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.

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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.

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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 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.

Nomenclature of a Split Master Link

Illustration 2	g02383724
(1) Snap Ring Counterbore (2) Bolt Threads (3) Mating Surfaces (4) Track Shoe Contact Surface (5) Track Shoe Key Slot (6) Bushing Bore (7) Bushing Strap (8) Bushing End Split Master Link Half (9) Wear Surfaces (10) Serrations (11) Pin End Split Master Link Half (12) Pin Bore

Note: Not all Caterpillar track shoes are produced with a Track Shoe Key Slot.

Cleaning

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Operating a power washer without proper protective equipment can result in personal injury. Wear the necessary protective equipment before operating a power washer. The necessary projective equipment includes a face shield, protective clothing and rubber gloves.

Before a master joint component can be properly inspected, the component is to be thoroughly cleaned and dried. Initially, the entire link assembly should be turned on the side and cleaned with a high-pressure water or stream washer. A high-pressure water or steam washer will remove large debris that has been packed into the master link. When the track has been disassembled the individual components must be cleaned in a wash tank, and allowed to dry.

Reusability Guidelines

Reusing master links when possible can reduce undercarriage costs. Inspect master links every time you service the track link assemblies. During a repair or reconditioning, correct any conditions that could have caused the original master links to fail.

Use the following criteria to determine if the master links can be reused:

• Master links should only be reused as matching sets. If either half cannot be reused, discard both halves. If one master link is replaced, the other adjoining master link should be replaced. Replacing the adjoining master link will avoid twisting of the track caused by unequal wear.

• Do not reuse master links if the halves have been welded together.

• Do not reuse master links if any serrations are missing

Illustration 3	g02387199
Master link missing serration

Do not reuse master links if any serrations are missing. Refer to Illustration 3.

Illustration 4	g02387338
Master Link with cracked serration

Do not reuse master links if any serrations are cracked. Refer to Illustration 4.

Illustration 5	g02387436
Master link excessive wear

Do not reuse master links if one or more of the serrations have excessive wear. Refer to Illustration 5.

Illustration 6	g02387470
Master link with slight wear on serrations

Reuse master links if three or less serrations show slight wear. Refer to Illustration 6.

Illustration 7	g02387747
Master link with burrs on the edges of the serrations.

Do not reuse split master links if burrs exist on the edges of the serrations. Remove the burrs from the edge of the serrations prior to reuse. Refer to Illustration 7.

Illustration 8	g02449016
Master link with burrs removed from the edges of the serrations.

Illustration 9	g02450457
Raised areas on the contact surface of the master link.

Do not reuse the split master link if the contact surface has raised areas. Remove the raised areas from the contact surface prior to reuse

Illustration 10	g02450656
Unacceptable fit (gap) between mating halves.

The gap between master link mating halve contact surfaces is to be less than 3.0 mm (0.12 inch). Remove excess or extruded metal from the contact surfaces prior to reuse. Contact surfaces of the master link are not to have a gap.

Illustration 11	g02451029
Arrow indicates a crack in the transition area of the bushing strap.

Do not reuse master links that have one or more cracks. The cracks may be small and difficult to detect. To detect the cracks, the link is to be thoroughly cleansed and inspected.

Illustration 12	g02451456
Damage to the threads of the master link.

Do not reuse the master links if threads are damaged. Refer to illustration 12. Check the threads for damage by using a new master bolt. Thread the new master bolt into the bore by hand. Ensure that the master bolt will travel to the bottom of the bore, by use of hand pressure. If the bolt does not turn into the master link by hand, discard the master link.

Illustration 13	g02452396
Wear step in the key slot of a master link.

Do not reuse master links if the track shoe slot is damaged or displays excessive wear. Refer to illustration 13.

Illustration 14	g02452456
Rolled over material that has extruded into the snap ring counterbore. Remove the rolled over material.

Reuse master links with snap ring counterbore damage after removing the rolled over material. If not removed, the rolled over material may prevent proper snap ring installation. A small grinder can be used to remove the rolled over material.

Illustration 15	g02452488
Minor track press damage.

Reuse master links with minor track press damage after removing burrs. Correct the tooling alignment before proceeding with the remainder of the disassembly. Refer to illustration 15.

Shipping Recommendations

To protect the serrations until installation of the tracks, use two triangular wood wedges, between the teeth and the underside of the track shoe. Then bolt link halves together using the master bolts.

If the track link assemblies are being shipped without the master shoes and bolts, use plastic plugs to protect the threads. Refer to illustration 16.

Illustration 16	g02452557
Plastic plugs can be used to protect the threads of the master link.

Installation Procedures

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To avoid personal injury, always wear eye and face protection when using pressurized air.

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Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressurized air, wear a protective face shield and protective clothing. Maximum air pressure at the nozzle must be less than 205 kPa (30 psi) for cleaning purposes.

Use the following procedure to install the master link bolts when the tracks are installed on the machine.

1. Use compressed air and a pick to clean all dirt, debris, paint, and rust from the serrations and bolt holes in each split master link.

   Note: Do not clean the threads of a master link with a tap.

2. Clean the threads of the master link with a fluted master bolt. The master bolt must be fluted by the technician. Three or four grooves are to be cut across the threads at an angle. Space the grooves an equal distance apart around the circumference of the bolt. Refer to illustration 17.
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   NOTICE
   Remove all burrs and raised areas around the fluted grooves, which may cause interference between thread surfaces.

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   Illustration 17	g02475795
   Fluted Master Bolt. Fluted grooves are to be cut by the technician.

3. Install the tracks on the machine and put the master links together. With the serrations of one master link fully engaged (no gaps), there must be no more than 3.0 mm (0.12 inch) gap between the serrations of the other master link. Refer to illustration 18. If there is more than a 3.0 mm (0.12 inch) gap, the misalignment must be corrected before proceeding.
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   Illustration 18	g02452636
   Ensure that the gap is correct. Refer to illustration 18 callout (A) for an example of a gap that is 3.0 mm (0.12 inch) or less. Illustration 18 callout (B) is an example of contact surfaces without a gap.

4. Lubricate the master bolt threads, body, and washer face with Loctite® C5-A® Copper-based Anti-Seize lubricant.

5. Install the master link track shoe. All four bolts should be turned all the way into the bores by hand. If the bolts do not turn freely, the binding or misalignment must be corrected before proceeding.

6. Tighten the bolts to the proper torque specifications. The torque specification can be found in Undercarriage Reconditioning Bulletin, SEBF8546, "Track Shop Servicing for Positive Pin Retention Track" or Undercarriage Reconditioning Bulletin, SEBF8557, "Track Shop servicing Procedure for Non-PPR Sealed and Lubricated Track".

Periodically check the master bolts for tightness. Master bolts are not to be reused.