15th edition

Custom TrackService Handbook

CUSTOMTRACK SERVICE

PEKP9400-03 Printed in U.S.A.R

Caterpillar

C

ustom T

rack Service H

andbook

CATERPILLARCUSTOM TRACK

SERVICEHANDBOOK

15th EDITION

1971, 1973, 1974, 1976, 1977, 1979, 1982, 1985, 1987, 1989, 1991, 1993, 1998, 2003

Caterpillar, Inc.

Printed in U.S.A. PEKP9400-03

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01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 1

I. General InformationMeasurement Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8Variables That Affect Undercarriage Life

Controllable Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11Non-Controllable Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Partially Controllable Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Percent Worn Charts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27Component Discussions

Links. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28Former Link Service Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Sealed and Lubricated Track Pins and Bushings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36Sealed Track Pins and Bushings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44Shoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51Idlers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56Carrier Rollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59Track Rollers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61Sprockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66Guards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71

II. Management & MerchandisingTrack Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74Destruction Wear Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74Track Seal Replacement Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75CTS Inspection Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79The Total Life Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81Cost Per Hour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87CTS on the Personal Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91Competitive Machine Undercarriage Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92

III. Elevated Sprocket MachinesManagement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96D4H, D5M, D5N, 561M, 561N .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110D5H, D6M, D6N, 517 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130D6H, D6R, 527 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148D7H, D7R, 572R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168D8L, D8N, D8R, 578, 583R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .188D9N, D9R.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202D9L, 589 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .212D10N, D10R .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .220D10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .228D11N, D11R .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .236

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IV. Low Sprocket MachinesManagement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .248Genuine Cat Undercarriage

D3, D4B, D4C, D4G, 931, 933, 935 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .258D4, D4D, D4E, 941 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .278D5C, D5G, 939. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .294D5, D5B, 951, 955, 561 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .310D6, D6B, D6C, D6D, 955 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .326D7, D7D, D7E, D7F, D7G, 977, 571, 572 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .348D8, 983. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .366D9, 594. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .378

Cat Classic UndercarriageD5B .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .390D6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .400D7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .410D8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .418

V. Hydrostatic LoadersManagement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .428943 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .436953 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .444963 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .460973 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .472

VI. ExcavatorsManagement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .490307, 308 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .498311, 312, 313, 314. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .508315, 317, 318, 320, 322, 320 FM .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .516320S, 322 FM, 325, 325 FM .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .530330 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .544330 FM, 345 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .556350 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .566365, 375, 385, 5080, 5090 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5745110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5845130 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5925230 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .602

205, 211, 213 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .608215 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .616225, 219, 215S.A., FB221, FB217, DL221 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .630225 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .646227, 229, 231, 225S.A., LL225 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .656235, LL235. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .666235 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .684245 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .692

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E70B.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .710E110B, E120B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .720E140 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .728E180, EL180 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .736E200B, EL200B .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .744EL240B, E240B, EL240, E240 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .752E300B, EL300B, EL300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .760E300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .768E450 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .776E650 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .784

VII. Paving Products/Drive BeltsPR1000, PR750B, SF550, SF500, TR500. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .794AP1050. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .800PR450B, SF350, SF250B, TR225B .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .808

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Edition Fifteen is a comprehensive update to the CTS Handbook. Nearly every wear chartin the book was updated. The General Information section, the Management & Merchan-dising section and the Management section of the four product types were also updated.

Some of the changes you will notice include: Cat Classic was added as a new section following Low Sprocket Machines. Nearly all wear charts were updated to some extent.

The rounding was removed from all measurements for the Ultrasonic Wear Indicator. The carrier roller wear limits were increased for use with Heavy Duty, Rotating

Bushing and Extended Wear Life Track. Track roller wear charts for elevated sprocket machines now extend to the point at

which the wear surface meets the retainer bolt holes. Greater and Lesser Allowable wear columns were combined into one for large

excavators. The machine layout is now similar to the PSK, starting with small machines and

ascending to the large ones. The machine models are up-to-date. Pipelayer model numbers were added to the applicable section headers. The three excavator sections, the 300-Family, 200-Family and E-Family, can be more

easily located with the new, individual tabs. Undercarriage Codes for use with the CTS computer program were updated and

included in the front of each section and below each wear chart. The track seal replacement guidelines were updated.

5

Introduction

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601.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 6

General Information

7

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 7

6V9413 CTS Tool KitSeparate Tools

PartNumber Description Use6V7784 CTS Pouch Carrying Tools8H8580 Scraper Cleaning U/C Components5P3920 12" Steel Rule With Caliper And Depth Gauge4S9404 4" Caliper Bushing O.D.8T7790 6" Caliper D11N, D11R Bushing O.D.4S9405 12" Caliper Roller Diameter5P3277 12'. Tape Track Pitch, D4H-D11R Sprockets5P8616 Sprocket Gauge D4-D5-D6 Sized Segments5P8617 Sprocket Gauge D7-D8-D9 Sized Segments6V9410* Depth Gauge Multi-Purpose All Models

* Replacement parts for the 6V9410 Multi-Purpose Depth Gauge:6V9409 10" Probe6V9408 4" Probe

The complete CTS tool kit allows you to quickly and accurately measure all undercar-riage components. Order the complete kit or individual tools from Parts Distribution.The tools provided in the Caterpillar CTS tool kit are high quality, high accuracy toolswhich will allow measurements to the closest 0.01" or 0.25 mm. Locally purchased sub-stitutes should have this accuracy and the depth gauge should have at least an 18" base tobe used for track roller measurement.

8

MEASUREMENT TOOLSGeneral Information

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 8

168-7720 Ultrasonic Wear Indicator III GroupSeparate Tools

Part Number Description168-7720 Ultrasonic Wear Indicator III Group168-7721 Ultrasonic Wear Indicator III168-7722 Ultrasonic Probe9U-7981 Couplant4C-5490 Couplant Holder6V-7145 Case (without foam insert)4C-4772 Foam Insert4C-3024 Battery Charger (120 or 230 volts, 50/60 Hertz)9U-6000 Paper Towels (16 towels)1U-7445 Rechargeable Batteries, Nickel Cadmium (AA)9U-6175* Ultrasonic Wear Indicator Soft Protective Case1U-9533* Non-rechargeable Batteries, Alkaline (AA)4C-5488* Cable Assembly, 9-pin female connector, for PC4C-5489* Cable Assembly, 25-pin female connector, for PC4C-5897* Cable Assembly for Telephone Modem

NEHS0730 Tool Operating Manual*Not included with the Ultrasonic Wear Indicator GroupNOTE: A 12-volt automotive power supply adapter (6 volts DC) and an earphone are available through manyelectronic supply retailers.

9

General InformationMEASUREMENT TOOLS

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 9

Ultrasonic Wear IndicatorThe ultrasonic wear indicator measures component thickness by sending high frequencysound waves through the material to be measured. The elapsed time between sendingand receiving the sound waves allows the tool to determine thickness. This electronic CTS tool has the following key features and benefits: Ultrasonic wave emitting probe Reduces time spent cleaning parts

(especially bushings and shoes). Eliminates measurement errors due to

dirt packing around parts. Measures bushings after turning. Eliminates errors due to measurement

technique differences among inspectors. Measures idler center flange wear.

Memory Reduces on-site measurement recording. Stores inspections for 64 machines. Downloads to CTS computer program for

automatic percent worn and projected life calculations.

Uploads previous inspections from CTS computerprogram to improve speed and quality

Language capability English, French, German, Portuguese, Spanish Earphone connector Allows users to hear Coupled beeping indicator Backlight feature Allows users to see the display in poor lighting

conditions

10

MEASUREMENT TOOLSGeneral Information

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Variables That AffectUndercarriage LifeThe variables that determine completeundercarriage system life and wear balancebetween components can be divided intothree major groupings. The first are thosewhich, to a great extent, are controllable.Controllable variables include track tensionadjustment (controlled by user operatingand/or maintenance personnel), shoe width(controlled by user operating and purchas-ing personnel) and on some models, align-ment (controlled by user and/or dealerservice personnel).The second major group, non-controllablevariables, discussed later in this majorsection include those life determiningfactors which are givens. They comewith the job. They are 100 percent deter-mined by the underfoot conditions andinclude impact, abrasiveness, packing,moisture, terrain and even application,meaning what the machine is doing.The final major group is sometimes calledpartially controllable variables and mainlyinvolve machine operator controllableevents such as habits.A thorough knowledge of each of theelements of all these three major groups isessential if the CTS expert is going to beable to not only explain what has hap-pened, but also what could be expected tohappen, especially as any of these variableswere to change. Awareness of the relativeinterplay between these variables on thefinal wear or structural life of specific com-ponents, and even on the system is soimportant that their discussion has beenplaced at the front of this book. To use therest of the book before understanding thesewould be counterproductive.

Controllable VariablesControllable variables that affect undercar-riage life must be separated out for dis-cussion because, in the case of at least thefirst two, they can have major economic

effect on the operation of undercarriagesystems.Track adjustment can have a very largeeffect on external bushing life, even to theextent of deciding whether a costly turnwill or will not be required to use up thelink-roller system. Track tension can alsoaffect track seal integrity. Track adjust-ment is controllable because the user canchange it.Shoe width, for which a detailed discus-sion follows, is controllable because theuser, with your advice, chooses whichshoe to order on his new machine and/orchanges to when the machine changestracks or even jobs. Shoe width as you willlearn can effect such widely ranging itemsas track seal and lubricant integrity to linkcracking to roller flange wear to bushingwear rate.Alignment, the third and least critical controllable variable is discussed herebecause, particularly on low sprocketmachines, it is wrongly blamed as a causefor many symptoms. It is beneficial toknow how misalignment does and doesnot affect wear patterns so you can betteridentify the real cause, controllable or not.A short discussion on track-excited vibration is also placed in this area eventhough it is only controllable at machinedesign time.

Track AdjustmentAlthough the method of measuring the reference sag and adjusting the track variesby machine type, the importance for thesedifferent machine types does not. As dis-cussed earlier, track over-tightening candrastically affect external bushing life(increasing wear rate as much as threetimes) and for this reason alone is listed fre-quently as a cause or accelerator underthe wear and structural problems section formany components. See separate machinesections for complete instructions on trackadjustment.

11

General InformationUNDERCARRIAGE LIFE VARIABLES CONTROLLABLE VARIABLES

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Shoe Width For Track-type MachinesTrack shoe width and degree of impact(bumpiness) can affect the wear life of theundercarriage. Since shoe width is a con-trollable variable, you can improve perfor-mance and wear life of the components bychoosing the right shoe.Use the chart on page 54 to help choosethe right shoe for a customer based on thefollowing factors.

Factors Affecting Machine ProductionFlotationChoose shoe width to provide adequateflotation, but not more than is needed. Thenarrowest shoe which provides adequateflotation will prevent the machine fromdigging in or sinking into underfoot mate-rial. Flotation increases proportionally toshoe width.Penetraction-TractionAdditional shoe width does not providegreater penetration or traction and conse-quently does not increase production assum-ing adequate flotation.ManeuverabilityAdditional shoe width increases turningresistance, making the machine harder tohandle and decreases productivity.VersatilityIncreased shoe width improves machineversatility allowing it to change from hardto softer underfoot conditions without los-ing flotation. However, increased shoe widthaccelerates wear and structural damage.

Undercarriage System Wearand Structural Life Factors Shoe Wear LifeWider shoes do not improve wear life. Theextra wear material provided by widergrousers gives a little extra life. The largestvariable affecting shoe wear life is slippage.Shoe Structural LifeBending stress on the shoe increases pro-portionately to the distance from the outeredge of the link to the end of the shoe.Cracking, bending and hardware looseningincreases as shoe width increases.Basic Rule of Thumb: Always specify thenarrowest shoe possible that will provideadequate flotation and traction withoutexcessive track slippage. See chart on fol-lowing page.Link-Roller-Idler Wear LifeWear rates increase on link rail sides,rollers and idler flanges as shoe widthincreases because of increased load inter-ference. Increased shoe width can alsoaggravate link cracking.Pin and Bushing Wear LifeExternal bushing wear rate on Sealed andSealed and Lubricated Track and internalwear rate on Sealed Track increases asshoe width increases in a given underfootcondition. This is due to the increasedloads, weight and twisting.Pin and Bushing Structural LifeToo wide shoes in high impact or steepterrain can cause pins and bushings toloosen in the link bores. This becomesmore evident with high single grousershoes. Loss of pin and bushing retentionprevents successful turn and replacementmaintenance.

12

SHOE WIDTHGeneral Information

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The following chart shows the effect oftrack link assembly bending stresses asshoe width increases.

Sealed and Lubricated Track Joint LifeThe most costly effect of too wide shoes inhigh impact conditions and/or steep terrainis the loss of lubricant and seal life result-ing in premature dry joints. The wider theshoe, plus the higher the impact, thegreater the chance of a pressed track jointopening up, allowing loss of lubricant.The loss of lubricant occurs when thebushing slides back and forth along the pin.The clearance between the links created bythis opening up is called end play. Endplay is permanent and can only be elimi-nated by pressing the components tight asat initial assembly or when track presswork is performed. For maximum lubricantand seal life the machine should beequipped with the narrowest possible shoeswhich will provide adequate flotation. In addition, shoes may have grouser cor-ners cut off to reduce turning resistance andbonding forces without loss of flotation andwith little loss of overall wear life.

ConclusionUsers should be aware of all the advan-tages and effects in productivity andwear/structural life factors when choosingshoe width. If all the symptoms of wideshoes are considered on the users machineand the causes are explained then he willbe able to choose the shoe width based ona better compromise between productivityand wear life.

13

General InformationSHOE WIDTH

20 22 24 26 28 30 32 34

Shoe Width

20

40

60

100

80

Bend

ing

Stre

ss%

Incr

ease

0

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 13

14

ALIGNMENTGeneral Information

Alignment for all Track Type Machinesexcluding *D9R (SN 7TL1212-up and8BL1422-up) *D10R (SN 3KR1331-up) and*D11R (SN 9TR202-up and 9XR154-up).Proper roller frame, idler and sprocketalignment is important to avoid accelerated,unbalanced wear on moving undercarriagecomponents (roller tread and flanges, linkrails and rail sides and sprocket segment orrim sides).As a general rule any wear pattern differ-ences between left and right, inner andouter, or front and rear may be due to

improper alignment of one or more partsof the roller frame, idlers or sprocket.Complete discussion on checking andmeasuring roller frame alignment plusstraightening procedures are discussed inSpecial Instruction SEHS8146-01 avail-able from Service Publications.Here is a description of the more commontypes of alignment problems, their cause,effect, and the steps required to correct thecause:*Note: These machines have unique Track RollerFrame alignment to increase link and roller life.This is further detailed in Service Magazine SEPD0469.

Roller Frame (including diagonal brace)Toe-In and/or Toe-OutWhen viewed from the top, either or bothof the roller frames is not parallel to thecenter line of the tractor.CAUSE: temporarily (during load only)or permanently bent diagonal brace orroller frameEFFECT: unbalanced wear when compar-ing inboard versus outboard roller andidler flanges and rail sides rollers wor-sen from rear to frontREMEDY: straighten diagonal braces andrepair mounting bearingsTiltWhen viewed from front or rear the rollerframe tilts toward or away from tractor.CAUSE: permanently bent diagonal brace,broken mountings or bearingsEFFECT: unbalanced wear when compar-ing inboard versus outboard roller, idler,link treads and flanges unbalance fromfront to rear on rollersREMEDY: straighten diagonal brace and/or repair mountings

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15

General InformationALIGNMENT

BowSimilar to toe-in and toe-out, but rollerframe is bent and curves in or out withrespect to tractor.CAUSE: bent roller frameEFFECT: similar to toe-in and toe-outexcept rear rollers are not affectedREMEDY: straighten roller frameTwistWhen viewed from the front, the rollerframe is twisted, with the front end of theroller frame tilted out.CAUSE: roller frame twisted around ahorizontal axis parallel to the tractorEFFECT: similar to effect of tilt exceptthat rear rollers should not be affectedREMEDY: straighten roller frame

Idler MountingToe-in or Toe-outWhen viewed from top, idler is not parallelto center line of roller frame.CAUSE: bent idler support box sections orbent idler yokeEFFECT: wears inner rail sides and idlerflanges most may affect wear on frontroller flangesREMEDY: straighten idler support boxsections or yokeIdler HeightThe distance that the tread of the trackidler is above the tread of the adjacenttrack roller.CAUSE: insufficient or excessive idlerheightEFFECT: as track roller tread wear anddamage, deterioration or loss of bogie padsoccur, and excessive machine vibrationmay result. Vibration is the result of insuf-ficient idler height. Excessive idler heightresults in poor dozing control, particularlywhile performing finish dozing operations.REMEDY: correct shimming

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16

ALIGNMENTGeneral Information

Lateral DisplacementWhen viewed from top, idler is parallel to,but moved toward or away with respect tothe tractor and roller frame.CAUSE: improper shimmingEFFECT: wears inner or outer idler flangesand inner rail sides selectively and mayaffect front roller(s) if severeREMEDY: correct shimming

Twist TiltWhen viewed from front, idler tilts out ofvertical plane.CAUSE: bent idler support box frame(inner and/or outer up and/or down withrespect to each other)EFFECT: same as toe-in or toe-outREMEDY: same as toe-in or toe-out

SprocketToe-in, Toe-outWhen viewed from top, sprocket notparallel to center line of roller frame.CAUSE: sprocket shaft bent forwards orbackwardsEFFECT: wears both inner link sides andboth sides of segmentsREMEDY: straighten or replace sprocketshaft

TwistWhen viewed from rear, sprocket is leanedor tilted in or out with respect to the rollerframe.CAUSE: sprocket shaft bent up or downEFFECT: inboard or outboard sprocketsides and rail insides worn selectively,may affect rear roller flangesREMEDY: straighten sprocket shaft

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17

General InformationALIGNMENT

General Statements about Alignment Problems,Symptoms, Causes, Effects and Remedies:

1. The larger and heavier the machine andthe more severe impact, the greaterlikelihood of temporary and permanentalignment problems.

2. Alignment problems of roller frameidler and sprocket will affect all linksthe same.

3. Alignment problems of roller frame,idler and sprocket will affect rollersunequally from front to rear and frominner to outer flanges and treads.

4. Horizontal straightness of roller framewill not affect track but will affect frontand/or rear roller treads compared tocenter.

5. Snaky track will not cause near thedegree of damage as compared to mis-alignment.

6. Carrier rollers can be used as a morevisual indicator of roller frame align-ment but are not as reliable as compar-ing track rollers.

7. If left side of tractor has different mis-alignment-type wear patterns thanright side, the problem is probably dueto permanent, rather than temporary,(working loads) causes.

8. Unbalanced loads due to side hilloperation will result in front to rearand left side to right side similarly inwear patterns on all parts affected.

9. If misalignment is suspected, it is impor-tant to at least measure the misalign-ment degree, if not completely correctit before installing new undercarriagecomponents.

10. Tight track increases the effect of alltypes of alignment problems becauseit increases the loads between theinterfering components.

For more complete descriptions and crossreference of specific component wear pat-terns that may be caused by misalignment,refer to the discussions under each compo-nent and model.

Lateral DisplacementWhen viewed from top or rear, sprocket isparallel to but moved in or out withrespect to tractor and roller frame.CAUSE: sprocket not pressed proper dis-tance onto shaftEFFECT: inboard or outboard sprocketsides and rail insides worn selectively,may affect rear roller flangesREMEDY: re-position sprocket on shaft

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18

VIBRATIONGeneral Information

Track-Excited VibrationTrack-excited vibration is the most widelyencountered vibration on track-type ma-chines. However, it is not understood bymany persons who work with these ma-chines. As the machine moves, each link,as part of an endless rail, makes contactwith two curved surfaces each with adifferent radius. These are the idler and thetrack rollers. Contact between the links,idler and rollers results in wearing of thelinks once-straight surface. The contactbetween the idler and the link creates aworn radius in the center of the link simi-lar to that of the idler.The track rollers have a similar effect onthe ends of the links, which are narrowedto permit them to overlap where they areconnected together. Because this overlapisnt 100 percent, the greatest amount ofwear is near the ends of the links, and thesize of the worn area has a radius similarto that of the track rollers. As a result ofthis wear, a scallop pattern is formed on thesurface of each track link. (See page 30).This type of link wear can be accelerated bythree factors abrasiveness and moisturecontent of the soil, machine weight andtravel speed and underfoot conditions.Rough underfoot conditions can placehigher loads at a given point on a link. It ispossible, on rocky or rough terrain, to havea higher load on a link on one side of themachine than on the other side. Althoughrough terrain can accelerate wear, it issometimes possible that track-excited vibra-tion will go unnoticed on rough terrain, yetbe apparent when the machine is workingon a smooth surface.Along with the depth of scallop, thescallop-roller spacing relationship is whatdetermines how smoothly the machinewill travel on the links. If the spacing ofthe track rollers and scallops are uneven,so that some of the rollers are on the highpoints of the links while others are over the low points, the machine will moveacross the scallops smoothly. However, ifthe spacing is the same, the rollers will rise

and fall in unison with each scallop as theypass over the links, thus creating vibration.Two factors, machine speed and the depthof the scallops, affect the amount of vibra-tion. The speed of the machine determinesthe frequency of the vibration while thedepth of the scallops controls the ampli-tude of the vibration. In addition, naturalfrequencies, which occur in all structures,can respond to the vibration. Because ofthis response, it is possible for certainparts of a machine, such as the roll-overprotection structure, sheet metal compo-nents, or, sometimes, the whole machine,to respond to the initial frequency andbegin vibrating.The vibration can be reduced by replacingdeteriorated isolation mounts where neces-sary, replacing any broken or missing fas-teners and by generally keeping the machinein good repair. A change in operating speedor technique, or a change of counterweightsor attachments may reduce the effect.

Testing and Adjusting FrontIdler Position and MachineBalance (D4H to D7R)Operator complaints of ride arise when amachine is vibrating more than normal.Abnormal vibration is generally caused byan idler that is lower than the track rollers,a machine that is not balanced, or scal-loped track links. Special Instruction entitled Adjustment ofthe Position of the Front Idlers and theBalance of the Machine for Improved Ride orImproved Fine Dozing, REHS0862-02, datedJune 01, 2001, covers the following topics: Correct Track Installation Measuring Grouser Rise Height Verify the Installation of the Correct Idlers Measuring the Depth of the Link Scallop Shim Charts for Idlers Measuring the Height of the Front

Idler Tread

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19

General InformationVIBRATION

Checking the Balance of the Machine Adjusting the Height of Center

Tread Idlers

Procedure to Determine Idler Height (D8L, D8N,D8R, D9L, D9N, D10, D10N,D11N Tractors)Model Applicable Serial Numbers

D8L AllD8N AllD8R AllD9L AllD9N AllD9R AllD10 AllD10N AllD10R AllD11N AllD11R All

As track roller tread wear and damage,deterioration or loss of bogie pads occur,and excessive machine vibration mayresult. This vibration is the result of insuffi-cient idler height. Idler height is the distancethat the tread of the track idler is above thetread of the adjacent track roller. See Illus-tration 1 for the area to be measured.

Illustration 1. Idler Height.

Under typical operating conditions, wearcauses the diameter of the track roller treadsto decrease at approximately twice the rateof the track idlers. When the front or rearrollers reach approximately 70 percent wear,the idler height may approach the minimumrecommended value. Variations in operat-ing conditions influence the wear rates.Additionally, the installation of new orrebuilt idlers on machines with partiallyworn track rollers directly affects idlerheight.To measure idler height, use the followingprocedure.

Illustration 2. Measurement points on a hard surface.

1. Move the machine to a hard, level sur-face. Inspect to make sure all bogie pads arein place. If any pads are missing or unser-viceable, they should be replaced.

Chart AFront Idler Front Idler Rear Idler Rear Idler

Model Nominal Minimum Nominal MinimumD8L 29 mm (1.142 in) 17 mm (.670 in) 34 mm (1.339 in) 10 mm (.394 in)

D8N, D8R 15 mm (.591 in) 10 mm (.394 in) 16 mm (.630 in) 10 mm (.394 in)D9L 23 mm (.906 in) 11 mm (.433 in) 27 mm (1.063 in) 11 mm (.433 in)

D9N, D9R 24 mm (.945 in) 11 mm (.433 in) 21 mm (.827 in) 11 mm (.433 in)D10 25 mm (.984 in) 14 mm (.551 in) 32 mm (1.260 in) 12 mm (.472 in)

D10N, D10R 26 mm (1.024 in) 14 mm (.551 in) 23 mm (.906 in) 12 mm (.472 in)D11N, D10R 32 mm (1.260 in) 14 mm (.551 in) 23 mm (.906 in) 12 mm (.472 in)

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 19

20

VIBRATIONGeneral Information

2. To check front idler height, carefullymove the machine in REVERSE until atrack shoe grouser is directly below thecenter of the idler shaft. See Illustration 2.3. Measure the distance (dimension X),between the bottom of the track shoegrouser in full contact with the surface andthe bottom of the track shoe grouser directlybelow the idler shaft.4. Repeat the procedure of aligning the trackshoe grouser directly below the center of theidler shaft on the rear idler by carefullymoving the machine forward. Measuredimension X for the rear idler.5. Idler height varies from model to modeland between front and rear idlers. Comparedimension X with the recommended nominaland minimum values for the front and rearidlers that correspond to your model asshown in Chart A.

Illustration 3. Measurement points on a soft surface.

Note: In the event that a suitable hardsurface is not available for checking idlerheight, a less accurate method may beused. See steps 6 and 7 below.6. Carefully move the machine inREVERSE until a track shoe grouser isdirectly below the center of the idler shaft.7. Stretch a length of string along the topedge of the track shoes. Dimension X ismeasured from the string to the pointwhere the center line of the idler shaftintersects the top of the track shoe which isdirectly below it. See Illustration 3 for thelocation of dimension X.

Illustration 4. Add plates at point Y.

Prior to adding plates under the bogie pads,raise the machine until the bogies are hang-ing free. Carefully support the machine. Seethe disassembly and assembly module inyour machines Service Manual for the cor-rect procedure.

8. If dimension X is less than the minimumshown in Chart A, plates should be addedbetween the lower bogie pad and the top ofthe major bogie assemblies at point Y. Theappropriate plates and their part numberare listed in Chart B. See Illustration 4 forthe correct location to add plates.The addition of one plate installed under afront or rear bogie pad increases idlerheight by approximately 7.50 mm (.295 in).In order to maintain uniform roller loading,equal number of plates must be installedunder the intermediate bogie pads. Takecare not to install more plates than are nec-essary to achieve the proper idler heightdimension. Excessive idler height results inpoor dozer control, particularly while per-forming finish dozing operations.

Chart BPlate Plate

Model Part No. ThicknessD8L 9P5543 5 mm (.196 in)

D8N, D8R 7T4699 5 mm (.196 in)D9N, D9R 7T5422 5 mm (.196 in)

D9L, D10N, 9P2704 5 mm (.196 in)D10R

D10, D11N, 8P8884 5 mm (.196 in)D11R

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 20

Non-Controllable VariablesThere are a number of variables that affectrates and patterns of wear which cannot becontrolled. These should be understood soyou can explain their effects.Non-controllable variables include soil andunderfoot conditions (abrasion, impact,packing, etc.), application conditions (whatthe machine is doing) and terrain conditions.

Soil & Underfoot ConditionsGenerally, soil and underfoot conditionscannot be controlled. They include theabrading, impacting, packing and evencorrosive and temperature effects of theimmediate environment.AbrasivenessAbrasiveness of underfoot conditions isthe most difficult to accurately measureexcept by its effect. We use these descrip-tions to identify relative abrasiveness interms of high, moderate and low:Abrasiveness Ratings DescriptionsHigh Saturated wet soils containing amajority of hard, angular or sharp sandparticles.Moderate Slightly or intermittentlydamp soils containing low proportion ofhard, angular or sharp particles.Low Dry soils or rock containing avery low proportion of hard, angular sharpsand or rock chip particles.The amount of moisture plays a big role indefining abrasiveness. For example, dry,pure quartz sand may be only 1/10 asabrasive as saturated wet, pure quartz sandslurry and only 1/2 as abrasive as it is in adamp condition. This is because moistureaffects the rate that particles are carried toand stuck to the metal surface being worn.Some abrasive combinations tend to attackthe bushing, others the grousers and stillothers the links and rollers. These differencesare difficult to quantify except by actual

experience, but you should be aware of thepossibility.Usually, the link is the best component touse for comparing overall relative abrasiveeffects because it is least subjected to othervariables at the same time. This is why weuse the link as the base or barometercomponent when comparing wear lives tothe service limit of different componentsin different abrasive conditions.ImpactImpact is not affected by other variablessuch as moisture or hardness of the parti-cles that make up the soil. It can bedefined as high, moderate or low. Impactis determined by weight of the machineand speed is defined under APPLICA-TION CONDITIONS later in this sub-section.Impact Ratings DescriptionHigh Non-penetratable hard surfaceswith constant exposure to 6" (15 cm) orhigher bumps.Moderate Partially penetratable surfaceswith constant exposure to smaller bumps.Low Completely penetratable surfaces(which provide full shoe plate support)with low exposure to any height bumps.The most measurable effect of impact ison structural problems such as bending,cracking, breaking, chipping, spalling,roll-over and hardware and pin andbushing retention. However, the degree ofimpact when combined with abrasivenessmay affect component wear rates andwear life by a factor of two or more. Forexample, a D6 dozing at a given speed oncompletely compacted or frozen sandy soilwith a deeply furrowed surface (highimpact) may get only one-half the wearlife on links as it would if the same soilwere loose, soft and smooth (low impact).Generally, wear life of larger machines areless affected by variations in impact thansmaller machines.

21

General InformationNON-CONTROLLABLE VARIABLES UNDERFOOT CONDITIONS

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 21

Wide shoes accentuate the effects ofimpact conditions. Machines with singlegrouser shoes are more susceptible tohigher impact effects than those withlower profile or multi-grouser shoes.PackingPacking describes any condition whereunderfoot material sticks to or packs betweenmoving undercarriage components. It hastwo major effects. First, it can prevent mat-ing parts from properly engaging eachother causing interference, high loads andincreased wear rates. The best examples ofthis effect is sprocket teeth packing, orpacking between shoe and bushings, caus-ing the teeth to engage the bushings underinterference.The second major effect of packing is itbinds abrasive particles to moving compo-nents thus increasing the wear rate. Thebest example of this is a sand-clay mixturepacked around idlers, carrier and trackrollers causing constant abrasion whenthese components turn. The result is similar to a grinding or polishing wheel.Parts subjected to this effect are usuallypolished smooth.Severe cases of packing will prevent therollers, particularly carrier rollers, fromturning. Then links must slide across rollertreads causing flat spots which are easilyrecognizable.Packing materials vary widely and extendfar beyond clay and mud that are normallyassociated with the above effects. The fol-lowing list of materials can result in one orboth of the major effects listed above.Obviously, the moisture content of most ofthese materials helps determine its sticki-ness and its compactability. Many under-foot conditions are composed of variouscombinations of these materials and theeffect may be cumulative. Packing materi-als fall into two categories; (A) those thatcan usually be extruded (squeezed out)from between the parts when wet and (B)those which cannot be extruded with thepressures and opening sizes normally avail-able in track type machines.

Packing MaterialsA Extrudable (when wet)

Sanitary Landfill (garbage)Silt soilsClay soilsSandy soilsSnow and iceMetallic ores (taconite)Non-metallic ores (gypsum)

B Non-extrudableSanitary Landfill (garbage)Branches, twigs and brushStones, rocks and gravelDemolition debrisSod-like materials

Generally, packing effects cannot be con-trolled except by constant cleaning orremoval.The most common modification to under-carriage components or use of option attach-ments involves providing Trapezoidalopenings for the packing type material toextrude (squeeze) or fall out, thus reliev-ing the pressure. These modifications orattachments should only be used in thepresence of extrudable type materials.(List A above)1. Trapezoidal Openings in shoes.

Caterpillar recommends that track shoeswith trapezoidal openings be used in thepresence of extrudable type material(see list A above). Track Shoes withtrapezoidal openings are available formost models from Caterpillar. The pro-cedure for dealers or users to cut trape-zoidal openings in shoes is described inInformation release memo UC89-17dated Oct. 4, 1989.

2. Roller guards should not be used inpacking type materials except whenrocks could enter between the rollersand cause crushing damage. Rollerguards prevent most materials fromextruding or falling out and cause moredamage than they prevent.

22

UNDERFOOT CONDITIONSGeneral Information

01.G.I.,M.&M (01-93) 7/11/03 3:40 PM Page 22

3. Mud and snow sprockets and segmentsshould only be used in the constantpresence of soft extrudable packingmaterials. In any other material theywill result in much accelerated externalbushing wear due to reduced contactarea in the sprocket root where the slotsare located. This is particularly true ofSealed and Lubricated Track becausethe bushing spends a greater period oftime exposed to the root area of thesprocket tooth.

Other Environment VariablesThere are other conditions that may ormay not be associated with the soil andunderfoot conditions.MoistureThe effects of moisture as contributing toabrasiveness and packing have beenexplained in the previous section. Moistureor water in itself can corrode (rust) steelresulting in the loss of wear material.Moderate amounts of moisture increasethe corrosive effects of many other chemi-cals and compounds; both those found innature and man made, such as sulfur, saltand fertilizers.Water in liberal amounts has the beneficialeffect of washing abrasive particles away,softening many packing materials to easetheir extrusion and finally, diluting somechemical corrosion agents to lessen theireffect.

ChemicalsCorrosive chemicals found in nature plusman-made compounds may have the effectof either eating away at wear material orincrease the rate of certain types of cracks.Ironically, most hardened steels are moresusceptible to corrosion and corrosioncracking than softer, unhardened steels.Highly acidic and saline soils can con-tribute to these effects.Organic chemicals such as petroleumproducts can attach rubber load rings andtoric rings in rollers and idlers causingthese to swell and fail.TemperatureThe effect of higher temperatures is toincrease the rate of chemical action.Extremely high temperatures like thosefound in slag removal in steel mills candamage seals and soften hardened steelsfound in undercarriage parts reducing theirstrength and wear resistance.The effect of temperatures below 32F(0C) is to freeze soils and water, creatingall previously discussed packing effectsfrom normally non-packing materials.Very low temperatures at -40F (-40C)can result in increased steel brittleness,(loss of cracking resistance) loss of rubbertype seal resiliency and reduction in thelubricant flow necessary in Sealed andLubricated Track and Lifetime Lubricatedroller and idlers.

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Terrain ConditionsAll application effects are influenced bythe terrain on which the work is beingdone. The most common effects aredescribed here regardless of the degree ofimpact, or the operating condition.

Working on SidehillShifts weight balance to the downhill sideof the machine; this increases the wearrate on the components on the downhillside of the machine. This increases wearon rail sides, roller and idler flanges,bushing ends, and grouser ends.

Working DownhillShifts weight balance forward causing rel-atively higher wear rate on front track andcarrier rollers. Due to design of track,working in forward minimizes rate ofbushing and sprocket wear.

Working UphillShifts weight balance to the rear causingrelatively higher wear on rear rollers andincreasing forward drive side sprocket andbushing wear.

Working on a CrownThe inner components carry heavier loads.This results in increased wear on innerlinks, rollers, idler treads and grouser ends.In extreme cases, the inner bushing-to-sprocket contact surfaces also may experi-ence greater wear.

Working in a DepressionCauses loads to be carried by outer (oroutboard) components, increasing wearrates on outer links, roller and idler treads,grouser ends and the outer bushing-sprocket contact surfaces in extreme cases.

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UNDERFOOT CONDITIONSGeneral Information

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Application ConditionsThe word applications, often misused todescribe underfoot condition, should bethought of as describing what the machineis doing. Below is a brief description ofthe possible wear and structural effect ofeach of several common applications,but without regard to what underfoot con-ditions the machine is in.Dozing and Push LoadingShifts machine weight toward the frontcausing faster wear rate on front rollersand idlers than on rear rollers.Ripping and DrawbarShifts the weight balance towards the rearof the machine with the effect of relativelyincreasing wear rate on rear rollers thanfront, and the sprocket and bushing inextreme cases.

LoadingShifts weight from front to rear of machineas it changes from digging to carryingrespectively. The greatest effect is increasedwear on front and rear rollers as comparedwith center rollers.Excavating with HydraulicExcavatorsShifts weight balance from left to right ofmachine with the possible effect of wearingouter link treads, roller treads and flanges ata greater rate than inner flanges and treads.

Partially ControllableVariablesSome of the variables affecting undercar-riage life can only be partially controlled.To some extent they may be influenced byuncontrollable variables but they can beoffset by the operator. We call these oper-ating conditions.The word operating, often misused todescribe the underfoot or application con-ditions, should be thought of in describing

what the machine operator is doing. Theseoperator induced variables may or may notbe a function of the underfoot conditions,the type of machine or even the applica-tion and terrain.SpeedWear rate is a direct function of speedbecause wear is a function of distancetraveled and not just the time worked.As speed increases, wear rates increase pro-portionally on all components. Wear ratesand impact (structural) effects also increaseproportionately with speed due to theincreased material loads caused by the rateat which the parts contact each other. Link-roller, link-carrier roller, link-idler and bush-ing-sprocket wear rates increase as a resultof the increased impact between theseparts. Shoe and grouser wear rates increasedue to the increased impact with the ground.High speed reverse has a particular effect onthe bushing-sprocket contact wear rates dueto the design of the track. Non-productivespeed should be discouraged. Non-productiveforward-reverse direction changes shouldbe avoided.TurningWear rates increase with increased turning.Turning increases interference loadsbetween links and rollers and links andidlers, particularly on rail sides and rollerand idler flanges. Turning in reverse canaccelerate bushing sprocket wear ascompared to turning in forward. The effectsof always turning in one direction can bebalanced by changing tracks from one sideof the machine to the other half waythrough their life.Slipping TracksWear rates on all components increasewhen tracks are slipped. Track shoegrousers particularly are affected whentracks are slipped due to the increasedsliding between the grouser and theground. The increased loads that slippingtracks cause is accelerated when theground is resistive to shear.

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Preferred-Side Dozing or Other WorkWear rates on the loaded side of a dozerwill increase on all components if only oneside of the machine is used. Wear ratesincrease as more power is applied to theloaded side. More slippage and packingwill occur on the loaded side; this alsoincreases wear.Putting more loads and packing onto oneside of the machine may result in up totwice the wear rate on that side. This wearrate effect may be balanced by switchingall components from one side to the other.This should be done when the link and/orrollers reach 1/2 their potential wear lifeon the most worn side.

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PARTIALLY CONTROLLABLE VARIABLESGeneral Information

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ComponentsEach component has individual measure-ment techniques, wear limits, wear charts,rebuildability criteria, wear patterns andstructural problems. The general informa-tion for each component is covered in thefollowing section. Specific additions andexceptions are covered in the individualproduct sections.

Percent Worn ChartsThe percent worn charts section of thishandbook translate direct component measurements into percent worn forCaterpillar parts only.Remember all percent worn figuresshown are percent of time used and notpercent of material used. This allows themto be used to directly calculate or projecttotal potential time (or life left) to theservice limit. These charts consider theslower rate of wear when the hardenedcase is still there and the faster rate ofwear that occurs when softer material isexposed. In some cases they also take intoaccount different expected wear rates afterthe service limit. In most cases they arenot straight-line relationships.Charts are provided for high and low impactapplications where applicable. Measure-ments corresponding to 100 percent worn(the service limit) are underlined.

In most cases, service limit projectionsmade from less than 30 percent worn cannot be considered accurate. However, suchprojections can be used to determine callback dates for remeasuring.Percentages above 100 percent have beenprovided so projections to 120 percentworn can be calculated. Backward projec-tions to service limit (100 percent) canalso be made to determine when theservice limit was reached. The extent ofpercentages shown beyond 100 percenthas no particular significance.Guidance for the selection of high, moderateor low impact and lesser or greater allow-able wear charts is provided at the front ofeach section of wear charts.A separate discussion under each componentsub-section (links, bushings, etc.) describeshow the service limit was derived and therisk involved when the component is wornpast that point.NOTE: Competitive undercarriage inspec-tion, wear life and maintenance/rebuildprojection cannot be determined frominformation contained in the handbookbecause of a lack of information aboutdesign, expected wear rates and servicelimits even when some important dimen-sions are similar.

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General InformationPERCENT WORN CHARTS

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Link Rail WearMeasurement TechniqueTrack links may be measured by the depthgauge or by the ultrasonic wear indicator.

The depth gauge measures link heightfrom the rail surface to the track shoe. Thecorrect location for track link measure-ment is outside of the links at the end ofthe track pin. Position the depth gauge asclose to the end of the pin as possible,making sure links and shoe surface areclean. Ensure the gauge is flat against thelink rails and perpendicular to the shoesurface. Measurement should be made tothe closest 0.01" or 0.25 mm.

The ultrasonic wear indicator measures thedistance from the rail surface to the bushingbore. Place the probe on the link above thecenterline of the bushing and slide theprobe along the tread surface to get thesmallest reading.

Wear LimitsLink wear limits are determined by settingthe allowable wear equal to some fractionof the clearance between the link and theroller. On some machines this clearance isbetween the link pin boss and the rollerflange. On other machines the clearance isbetween the bushing and the inner flangesof a double flange roller.On a 100 percent worn link matchedtogether with a 100 percent worn roller,the roller flanges are in contact with eitherthe link pin bosses or the bushing. As wearproceeds past 100 percent, wear on thelink pin boss reduces pin retention, wearon the bushings may cause cracking, andwear on the roller flanges reduces trackguiding and roller rebuildability.If the link is worn to approximately 120 per-cent, structural damage may result in theform of cracking, breaking and pin andbushing loosening.Wear ChartsWear charts for links have a built in factorallowing for faster wear rate as the hardnessof the steel decreases below the hardenedcase depth. This is true for all componentswhere the allowable wear is greater than thehardened case depth.Different wear charts are provided for dif-ferent links, and for the same link runningwith different rollers, each of which isdetermined by part number within a givenundercarriage or machine size.RebuildabilityTrack links can usually be successfullyrebuilt with submerged and/or automaticwelding to replace the worn away rail(top) surface if the link meets the follow-ing criteria:

1. Rail wear measured over the pin bossis between 70 percent and 100 percent.

2. Unevenness of rail height is not excessive.

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LINKSGeneral Information

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3. Rail side wear due to roller flange orguiding guards or inside rail gougingby the sprocket hasnt reduced railwidth significantly.

4. Pin boss is not worn enough to causereduced pin retention.

5. Counterbore depth and elongation wear(with Sealed Track) will not signifi-cantly affect resealing of the pins andbushings.

6. Face wear (area surrounding the link,bushing and counterbores) has notreduced the thickness of the rail in thatarea by more than 20 percent.

7. Rail spalling hasnt caused more than30 percent of the rail surface to beremoved.

8. Links are not cracked through in therail, pin and bushing bores or shoestrap sections.

9. Bolt holes are not wallowed out orelongated to prevent adequate shoeretention.

10. Pin and bushing bores are not damaged(broached) as to prevent adequate pinand bushing retention.

With proper welding techniques and mate-rials, the fully rebuilt (to 0 percent wornheight) rail should provide about 80 percentof the original life to the service limit. Thispercentage may be reduced as impact levelincreases. By running the rebuilt rail to120 percent it should provide about 100 per-cent of the original rail life to the servicelimit potential.

Sealed and Lubricated Track vs.Sealed Track track link effectsDue to the expected absence of internalwear, counterbore depth and elongationwear and face wear should be eliminated.This increases successful rebuildabilitycompared to the same link used withSealed Track. Absence of internal wearand snakiness should also reduce thedegree of rail side wear, uneven rail wear,inside rail gouging and guiding guardwear, and possibly increase original andrebuilt rail wear life. If snakiness is experi-enced with Sealed Track, the lack of snak-iness in Sealed and Lubricated Track mayextend link life by up to 20 percent.

Link Wear Patterns

Rail (Top) Wear(Normal expected wear position)CAUSES: Rolling and sliding contact withroller and idler treads.ACCELERATORS: Horsepower, weight,speed, impact, abrasiveness, shoe width,tight track and snakiness.EFFECT: Wear limit reached when rollerflanges begin to contact top of pin boss.REMEDIES: Eliminate or reduce control-lable accelerators listed above and rebuild(weld) to desired rail height.

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30

Uneven (Scalloping) Wear on Rail TopCAUSES: No. 1 & 3: Faster wear rate due toreduced contact with rollers at narrower linkoverlap area (also see Face Wear on page 31).CAUSES: No. 2: Sliding wear due to reducedcontact area with idler at center of link rail.ACCELERATORS: Same as Rail (Top)Wear above, particularly tight track.EFFECT: No. 1 & 3: Wear limit over pinboss reached prematurely.No. 1, 2 & 3: Reduces rebuildability andcauses vibration in extreme cases. Counter-weighting machines will reduce wear. A1/4" difference will cause a ride problem.REMEDIES: Same as Rail Top Wearabove. Sealed and Lubricated Track willhave less wear in areas No. 1 & 3 due to nopitch extension. Better balance will reducevibration and potential cracking in cab.

Pin Boss Side WearCAUSES: Sliding contact with guidingand/or roller guards plus abrasives (maybe seen at either or both ends of pin usually more severe on outboard side).ACCELERATORS: Uneven terrain andside hill operation. Too-wide shoes, wornrolling component flange, misalignment andsnaky track are main controllable variables.REMEDIES: Eliminate or reduce control-lable accelerator variables, particularlysnaky track by turning pins and bushings.

Rail Side Wear (inside and/or outside)CAUSES: Rolling and sliding contactwith roller and idler flanges.ACCELERATED BY: Same as Rail TopWear plus uneven terrain, turning, sidehill operation, misalignment, too wideshoes and snakiness of unsealed or SealedTrack.EFFECT: Reduces rail wear life to servicelimit and rebuildability.REMEDIES: Reduce or eliminate control-lable accelerators, particularly snaky track,tight track and too wide shoes.

Rail Inside GougedCAUSES: Sprocket tooth tip interferingdue to snaky track and/or misalignment oftrack or sprocket (see sprocket wear).ACCELERATORS: Side hill or uneventerrain, turning, too wide shoes.EFFECT: Reduced rebuildability of linksand reusability of sprocket segments ifsevere.

REMEDIES: Correct controllable causesand accelerators.

LINKSGeneral Information

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Elongation of CounterboreCAUSES: Rotating contact with thebushing end in pitch extended SealedTrack (see Sealed Track bushing counter-bore wear).ACCELERATORS: None a directfunction of pitch extension.EFFECT: Reduces re-sealability of coun-terbore even with new seals in SealedTrack. Link is less rebuildable.REMEDIES: Turn pins and bushings inSealed Track at service limit.

Depth Wear in CounterboreCAUSES: Rotative contact betweenSealed Track seals or bushing end withbottom of counterbore (See Sealed TrackBushing End Wear).ACCELERATORS: Abrasiveness, sidehill loads and turning, side thrust impactand too wide shoes.EFFECT: Same as Counterbore Elonga-tion wear.REMEDIES: Reduce or eliminate control-lable accelerators and install new seals atpin and bushing turn time.

Pin Boss Tip WornCAUSES: Sliding and roller contact withroller flange tops (see roller flange wear).ACCELERATORS: Nonuniform front torear roller wear when link is not 100 per-cent worn.EFFECT: Loss of pin retention and reducedrail rebuildability.REMEDIES: Swap rollers to balance weareffect and rebuild rail, rollers as required.

Face WearCAUSES: Rotative contact between over-lapping link faces following Sealed Tracklink counterbore depth wear, seal wear andbushing end wear, all which allow endplay.ACCELERATORS: Same as Depth Wearin Counterbore.EFFECT: Reduces wear life of originaland/or rebuilt link and reduces rebuildabil-ity. (Also see Uneven Wear On Rail Top,position 1 & 3).REMEDIES: Reduce or eliminate acceler-ators. Sealed and Lubricated Track willhave very little face wear due to no coun-terbore or bushing end wear keeping linkfaces separated.

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Pin Boss End - Guiding Guard WearCAUSES: Sliding contact between pinboss ends and guiding and roller guards.ACCELERATORS: Same as rail side wear.EFFECT: Reduces pin retention and there-fore limit rebuildability.REMEDIES: Reduce or eliminate all control-lable accelerators related to loads conveyedfrom shoe to link, keep bolts properly torquedand use narrowest shoe possible.

Link Structural ProblemsRail Spalling

CAUSES: Repeated high impact contactwith roller treads and/or flanges.ACCELERATORS: Impact, MachineSpeed, Horsepower, Weight: too wideshoes, and tight track.EFFECT: May reduce wear life rebuild-ability if over 30 percent of rail surface isaffected otherwise only a cosmetic effect.REMEDIES: Reduce or eliminate control-lable Accelerators, particularly too wideshoes that add weight and leverage loadson uneven terrain.

Link CrackingCAUSES: Repeated twisting of link.ACCELERATORS: Same as Rail Spall-ing plus degree of rail material wornaway. The biggest accelerator is shoes thatare too wide.EFFECT: Shorten link assembly life, trackseparation if cracked through and preventsrebuilding.REMEDIES: Reduce or eliminate control-lable accelerators particularly too wideshoes and tight track.

Pin & Bushing Bore EnlargementCAUSES: Bore material broached outduring assembly and/or disassembly; plusmaterial worn out during sliding movementof flexing pins and bushings.ACCELERATORS: Same as Rail Spallingplus material worn off of pin bosses. Thebiggest accelerator is shoes that are too wide.REMEDIES: (1) Improved track pressalignment and tooling to prevent broach-ing during assembly and disassembly. (2)Reduce or eliminate controllable accelera-tors especially too-wide shoes and tighttrack.

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NOTE: Links in Sealed and LubricatedTrack should generally experiencereduced pin and bushing bore enlarge-ment and subsequent retention loss. This isdue to the absence of internal wear, whichin Sealed Track increases flexing of pinsand bushings in their bores.There should be less flexing of Sealed andLubricated pins and bushings because thebushing is held more rigidly between thelink counterbores over its entire life andthe pin is held more rigidly within thebushing during its life.

Split Master Link

The two piece split master link allowseach joint to be factory or dealer sealed inthe shop.Measuring and interpreting master link railand other wear patterns is the same for thesplit master link as for regular link. Splitmaster link rebuildability is determined bythe same criteria plus the condition of theconnecting teeth and the bolt hole threads.Split master link structural problems areusually related to improper assemblyand bolt torquing. Split master links areeven more susceptible to detrimentaleffects of wide shoes.

Assembling and TorquingProcedureThe importance of proper assemblysequence and torquing cannot be over-stressed. Follow these steps for both newand used split master links.1. Before installing the track, the point of

connection for the master link must beclean and not have damage. Remove allpaint from points of connection.

2. Put 2P2506 Thread Lubricant or5P3931 Antiseize Compound onthreads of master bolts.

3. Put master links together and checkalignment of holes for master bolts.Install one master bolt in each link. Thebolts must turn easily in the threads,when turned by hand.

4. Remove the bolts. Install the mastertrack shoe and all four master bolts.Turn the master bolts by hand.

5. Tighten the master bolts to initial torque,plus 1/2 or 1/3 turn. The actual Torquespecifications can be found in the Man-agement section of each machine type.

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Former Link Service LimitsThese former links do not appear on the wear chart pages. But, by using this procedureand chart, you can calculate the percent worn measurement.

STEP 1 STEP 2 New Link Height - Worn Link Height = Amount Worn Amount Worn

Allowable Wear x 100 = Percent Worn

Track Link New Link AllowableModel Pitch Part Number Height Wear Service

D2 6.12" 5B3129 & 30 3.00" .25" 2.75"(155.4 mm) (76.2 mm) (6.4 mm) (69.9 mm)

D3 6.125" 6S3143 & 44 3.18" .26" 2.92"155.3 mm (81 mm) (7 mm) (74 mm)

D4 6.75" 5K9423 & 24 3.66" .25" 3.41"(171.5 mm) (93.0 mm) (6.4 mm) (86.6 mm)6.75" 5K9457 & 58 3.66" .25" 3.41"(171.5 mm) (93.0 mm) (6.4 mm) (86.6 mm)6.75" 4K6647 & 48 3.66" .25" 3.41"(171.5 mm) (93.0 mm) (6.4 mm) (86.6 mm)6.75" 4K7039 & 40 3.66" .25" 3.41"(171.5 mm) (93.0 mm) (6.4 mm) (86.6 mm)6.75" 6B4645 & 46 3.53" .25" 3.28"(171.5 mm) (87.7 mm) (6.4 mm) (83.3 mm)

D5 6.91" 5S683 & 84 4.06" .37" 3.69"(175.5 mm) (103.1 mm) (9.4 mm) (93.7 mm)

D6 8.00" 9M5627 & 28 4.50" .30" 4.20"(203.2 mm) (114.3 mm) (7.6 mm) (106.7 mm)6.75" 2S5959 & 60 4.00" .34" 3.66"(171.5 mm) (101.5 mm) (8.6 mm) (93.0 mm)6.75" 7M8863 & 64 3.91" .30" 3.61"(171.5 mm) (99.3 mm) (7.6 mm) (91.7 mm)6.75" 1M1431 & 32 3.91" .30" 3.61"(171.5 mm) (99.3 mm) (7.6 mm) (91.7 mm)6.75" 5H8679 & 80 3.78" .30" 3.48"(171.5 mm) (96.0 mm) (7.6 mm) (88.4 mm)

D7 8.50" 2S1749 & 50 4.75" .35" 4.40"(215.9 mm) (120.7 mm) (8.9 mm) (111.8 mm)8.50" 1M9001 & 02 4.75" .35" 4.40"(215.9 mm) (120.7 mm) (8.9 mm) (111.8 mm)8.00" 1S6433 & 34 4.63" .38" 4.25"(203.2 mm) (117.6 mm) (9.7 mm) (108.0 mm)8.00" 7M8085 & 86 4.50" .38" 4.12"(203.2 mm) (114.3 mm) (9.7 mm) (104.6 mm)

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Track Link New Link AllowableModel Pitch Part Number Height Wear Service

D7 8.00" 1S1863 & 64 4.62" .38" 4.24"(203.2 mm) 1S6433 & 34 (117.5 mm) (9.7 mm) (107.5 mm)8.00" 7M6763 & 64 4.50" .38" 4.12"(203.2 mm) (114.3 mm) (9.7 mm) (104.6 mm)8.00" 2M7265 & 66 4.50" .38" 4.12"(203.2 mm) (114.3 mm) (9.7 mm) (104.6 mm)8.00" 2H959 & 60 4.50" .38" 4.12"(203.2 mm) (114.3 mm) (9.7 mm) (104.6 mm)

D8 9.00" 1S4033 & 34 5.25" .42" 4.83"(288.6 mm) (133.3 mm) (10.7 mm) (122.7 mm)9.00" 2M8813 & 14 5.12" .38" 4.74"(288.6 mm) (130.0 mm) (9.7 mm) (120.4 mm)9.00" 1M1447 & 48 5.12" .37" 4.75"(288.6 mm) (130.0 mm) (9.4 mm) (120.7 mm)9.00" 9M3843 & 44 5.12" .37" 4.75"(288.6 mm) (130.0 mm) (9.7 mm) (120.7 mm)8.00" 1S8839 & 40 4.97" .38" 4.59"(203.2 mm) (126.2 mm) (9.7 mm) (116.6 mm)8.00" 7H3799 & 800 4.88" .33" 4.55"(203.2 mm) (124.0 mm) (8.4 mm) (115.6 mm)8.00" 2H953 & 54 4.75" .37" 4.38"(203.2 mm) (120.7 mm) (9.4 mm) (111.3 mm)

D9 10.25" 8M6901 & 02 5.56" .37" 5.19"(260.4 mm) (141.2 mm) (9.4 mm) (131.8 mm)10.25" 2M5649 & 50 5.56" .37" 5.19"(260.4 mm) (141.2 mm) (9.4 mm) (131.8 mm)9.00" 2M1623 & 24 5.25" .35" 4.90"(228.6 mm) (133.4 mm) (8.9 mm) (124.5 mm)9.00" 2F5879 & 80 5.00" .38" 4.62"(228.6 mm) (127.0 mm) (9.7 mm) (117.3 mm)

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Sealed and Lubricated TrackBushing WearMeasurement TechniqueThe track bushing is the most importantcomponent in the undercarriage to measureand interpret accurately.To do this, three measurement methodsare available, each using tools provided inthe CTS tool kit.You should refer to individual model family sections for specific recommenda-tion on which method to use because the second method described here, usingdepth gauge will record vertical positionwear only.

1. Caliper MethodThis method gives a direct reading ofbushing diameter. With careful cleaningand proper technique it can yield the mostaccuracy, but is also the most susceptibleto error if not properly measured. Themost common errors using the calipermethod are:

(A) Calipers Squeezed Too Tight Calipers that are over tightened can bespread like a spring and will give too smallof a reading.

(B) Calipers at Wrong Angle to BushingAxis Calipers that are set at an angle to thebushing will give an oversize measurement.

(C) Calipers Not Slid Back and ForthAcross Position to be Measured Calipers that are not passed back and forth over the maximum diameter of thebushing position being measured will givean undersize reading.

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(D) Bushing not Cleaned Well BeforeMeasurement If the bushing surface isnot cleaned the measurement taken will beoversized.

(E) Calipers Not Placed at Most WornPortion of Bushing If the caliper is located inboard or outboard of the minimum diameter along its length in agiven wear position the reading will beundersized.

PRACTICE!The best way to practice measuringbushing wear is with bushings removedfrom the track. You should be able torepeat the measurements made by yourselfand others with an accuracy of .01" ( 0.25 mm).

2. Depth Gauge MethodThe method for measuring the verticalposition of bushings uses the same depthgauge used for links. This method is morefree of the measurement technique errorsencountered with the caliper, but may besubject to slight track link dimensional dif-ferences and track shoe bending. It is alsosubject to the same technique errors aslink height measurements. These include:(a) parts not cleaned, (b) depth gauge basenot positioned correctly with respect tobushing length and (c) depth gauge probenot forming a perpendicular or 90 anglewith the shoe.Disadvantages of the depth gaugemethod(A) Cannot determine reverse or forward

drive side wear, which is critical inmost applications.

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Advantages of the Depth Gauge Method(A) Absolutely insures vertical position is

being measured (unless measured at apoint where track is bent).

(B) Averages diameter measurement oftwo adjacent bushings for greateraccuracy.

(C) Backside of bushing can be measuredafter bushing turn (the importance ofthis will be explained in the next discussion).

3. Ultrasonic Wear Indicator MethodThis method is the most accurate becauseit directly measures the most criticaldimension, bushing wall thickness. It alsocan be used to accurately measure thebackside of bushings after a bushing turn.

Measure the bushing wall thickness byslowly sliding the probe around thereverse, vertical, and forward drive sides.Use the smallest dimension to determinepercent worn.

Sealed and Lubricated TrackBushing WearMeasurement PositionsRefer to individual product sections forspecific guidelines.Wear Limits Greater and LesserWear limits for Sealed and Lubricated Trackbushings are determined by remaining crackresistance strength. Two percent worncolumns titled lesser allowable wear and

greater allowable wear are provided inbushing wear charts. At 100 percent worn,the lesser allowable wear column pro-vides more bushing wall thickness than thegreater allowable wear column. Note, forexample, in the wear charts under the ultra-sonic measurements, the bushing wall isalways thicker, and thus more crack resis-tant, on the lesser allowable wear columnthan on the greater.The selection of the optimum allowablewear column will maximize the link andbushing life while preventing bushingcracking. The optimum percent worncolumn depends on the relative bushingcrack resistance required in your situation.The amount of required crack resistancedepends on several factors includingsprocket position (high or low), underfootconditions, bushing projected life, andapplication. Refer to the managementsection in front of each product section forthe criteria to use in selecting which allow-able wear chart to use.Wear ChartsThe expected wear rate through the allow-able wear limit is determined from severaltests. These rates are built into the wearcharts so that accurate projection to 100 per-cent worn and 120 percent can be madeassuming uniform abrasive, impact andother conditions will continue. The built-inbushing wear rate after the hardened case hasbeen completely worn through is approxi-mately 2 times the rate expected in the hard-ened case depth.Like with most other components, projec-tions made to the service points based onless than 30 percent worn will not beaccurate. The wear charts provide thepercent worn equivalent for those mea-surements less than 30 percent only forprojecting re-visit or re-measurementpoints. The bushing is the most likelycomponent to use for this re-measurementprojection.

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Sealed and Lubricated Track vsSealed Track EffectsDue to expected absence of internal wearthe Sealed and Lubricated Track bushingshould have its most worn position on orvery near the vertical position. SealedTrack is expected to have either forwardor reverse position as the most criticalposition. The Sealed and Lubricated Trackbushing also has fewer wear positions toanalyze.The expected life of the Sealed and Lubri-cated Track bushing is approximately 50 per-cent more than the Sealed Track bushingwhen compared to either high or low impactservice limits.These increases depend on the following:1. Degree of internal wear that contri-

buted to the external wear on theSealed Track bushing.

2. Properly adjusted track.3. Absence of very severe packing.4. Similar working conditions.Sealed and Lubricated TrackBushing TurnabilityThe Sealed and Lubricated Track bushingshould be turned based on the guidelinesin following sections entirely devoted tospecific model families.The bushing may be expected to providelife after turn wear, equal to or exceedingthe wear life potential of the first or frontside prior to the turn. Sealed and Lubricated Track bushings canbe successfully turned wet if there are nocracks through the bushing wall at turntime and seal wear life guidelines havenot, or will not, be exceeded.Sealed and Lubricated Track bushingsmay be successfully turned dry, (with orwithout internal wear at turn time) as longas there are no cracks through the bushingwall and internal wear does not exceedSealed Track service limits.

Life after dry turn cannot be expressedas a percent of wet life before turn. It willmost closely approximate life after turnof Sealed Track in hours, not percent.

How to Interpret Sealed & Lubricated Track Bushing Wear PatternsThese patterns are found on wet joints. Fordimensions on wear patterns of dry jointssee Sealed Track bushings.

Vertical Position (0 to 30 from vertical is normal expectedwear pattern)CAUSES: Sliding contact with root ofsprocket tooth during forward to reversedirection changes and due to pitch mismatchfrom minor packing and advanced othercomponent wear.ACCELERATORS: Horsepower, weightand speed; impact, abrasiveness, tighttrack and packing loads, worn rear rollers,wide shoes and reverse loads.EFFECT: Cracking will occur whenrespective high or low impact wear limit(100 percent worn) is exceeded. Bushingwall will break through at destruction point.REMEDIES: Eliminate or reduce control-lable accelerator variables listed above andturn bushing on or before service limit.

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Reverse and/or Forward Drive Side(30 to 60 from vertical)CAUSES: Same as VERTICAL POSI-TION except degree of packing is moder-ately severe.ACCELERATORS: Same as VERTICALPOSITION but particularly tight track.EFFECT: VERTICAL POSITION shouldovertake FDS or RDS as most wornposition in later hours if track is properlyadjusted and new segments are notinstalled prematurely.REMEDIES: Eliminate controllable accel-erator variables, particularly tight track.Bushing should be turned at or beforeservice limit.

Reverse and/or Forward Drive SidePocket Wear (60 to 90 from vertical)CAUSES: (1) Same as VERTICAL andFDS/RDS except packing is very severe.(2) Track is too loose causing backjam-ming as reverse motion at bottom ofsprocket on RDS only.ACCELERATORS: (1) Same as VerticalPosition and FDS/RDS (2) Same asVertical Position and FDS/RDS excepttrack tension, which needs to be increased.Uphill reverse loading of machine withtoo loose track is biggest accelerator.

EFFECT: (1) Vertical position shouldovertake either pocket as most wornposition in later hours if track is properlyadjusted and new segments are notinstalled prematurely. (2) Track may jumpon sprocket if sprocket tooth tip height isworn excessively and track remained tooloose.REMEDIES: (1) Eliminate or reduce con-trollable accelerator variables. Turn bushingbefore this position reaches 120 percentregardless of the vertical position percentworn. Do not install new segments prema-turely. (See discussion on use of sprocketreuse gauge.) (2) Adjust track as recom-mended in the individual product sections.Install new segments only if tip height isreduced significantly and there is no mod-erate to severe packing. Turn bushingsbefore this position reaches 120 percentregardless of vertical position percent worn.

Off Center WearCAUSES: Misalignment of track andsprocket.ACCELERATORS: (1) Various rollerframe and sprocket alignment problems.(2) Worn rear guiding and/or final drive-guiding guards. (3) Side-hill operation.EFFECT: Should not increase wear rate ofbushing to wear limits, but may reducebushing retention if accompanied by impact.REMEDIES: (1) Correct alignment. (2)Replace guiding and final drive-guidingguards.

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Roller Flange WearCAUSES: Track Rollers inner flangesand/or carrier roller flanges contactingbushing due to one or more of (a) links (b)carrier rollers or (c) track rollers beingwell past 100 percent worn.ACCELERATORS: All load variables.EFFECT: Causes bushing to be prema-turely worn to limit.REMEDIES: (1) Turn bushing on or before100 percent worn in these positions. (2)Rebuild, swap or replace carrier rollersshells or roller shells.NOTE: Refer to pages 66 through 69 forrelated discussion on sprocket wear patterns.

Sealed and Lubricated TrackBushings Structural ProblemsThe destruction limitation of track bushingsis usually due to (1) wall cracking (breakingout in the severe case) or (2) loose bushingretention in the link. In the case of Sealedand Lubricated Track, either of these willresult in a dry joint (lubricant loss), and inmost cases impair parts reusability.

Bushing Cracks (Through the wall)CAUSES: Exceeding wear limit for respec-tive degree of impact or other criteria.ACCELERATORS: Same as VerticalPosition wear pattern.EFFECT: (1) Loss of lubricant and result-ing internal wear. (2) Makes bushing non-reusable in wet joint and may not bereusable at all if a piece is broken out of adry joint.REMEDIES: Re-evaluate decision to runpast wear limit.

Bushing (and/or Pin) Loose in LinkCAUSES: Loss of press-fit into link bore.ACCELERATORS: (1) Severe repeatedimpacts yield or crack link bore. (2) Linkbore broached by improper press align-ment at reassembly time.EFFECT: (1) Loss of lubricant. (2) Pin,Bushing and Links not reusable in wet ordry joint.REMEDIES: (1) Reduce or eliminate con-trollable variables which accelerate impact.(2) Control track press alignment capability.

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Dry Sealed and LubricatedTrack JointsPremature dry joints in Caterpillar Sealedand Lubricated Track may be detected byany of the following methods:1. Hand feeling for relatively warm bush-

ings (or pin ends) after the machine hasbeen operating.

2. Measuring or seeing pitch extended(internal wear) section of track. Use ultra-sonic wear indicator to measure internalwear, if external wear is not visible.

3. Finding bushings significantly moreworn than others in the same track.

No effort should be made to re-lubricate torestore the joint to lubricated integrity withnew parts in the field once dry enough tofeel heat