The idler is measured with a depth gauge using four points that are then averaged for the final measurement. The exact process is shown in the video below.
Potential Observations
What to look for
Below are some of the issues you should be looking for when inspecting an idler. This list does not cover all possible issues, but is a starting point that covers most genral issues.
Flattened Tread Wear
Link Overhang Wear
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Model specific — Accentuated by elevated design • Improper rebuild of idler at dealer shop |
• Visual or cosmetic • Can lead to uneven link wear |
• Cosmetic • Continue to run • Review rebuild procedures |
Center Flange Side Wear
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Sidesloping • Constant turning in same direction • Misalignment of carrier roller • Worn guide guards • Twister resister wear • Equalizer end bearing wear • Wide shoes |
• Reduces idler tread rebuildability • Inside link rail wear |
• Alternate slideslope working • Change direction of turning • Align carrier roller • Replace guide guard wear strip and/or align guide guards • Check twister resister & equalizer end bearing wear; Service if necessary |
Center Flange Top Wear
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Abrasive &/or rock wearing between center flange & track roller frame | • Primary guiding of link as. by idler • Inaccurate idler wear by CTS • Effects rebuildability in extreme cases |
• Rebuild center tread diameter to Cat recommendations at Rebuild time — Reference Reconditioning Guide • Add guarding to prevent abrasion &/or rock entry |
Uneven Tread Wear (Inner/Outer)
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Wide shoes • Twisting of track frame • Sidesloping |
• Difference in idler tread wear measurement | • Monitor wear difference • Swap idlers side to side • Use narrower shoes • Directional changes when sideslope working |
Tread Spalling
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• High edge loading • Wide shoes • Tight track • Poor rebuild practice |
• Reduce tread wear material • Uneven link wear |
• Generally cosmetic • Continue running • Spalled surface will wear away • Proper track adjustment • Repair or replace if excessive spalling • Review rebuild procedures |
Radial Tread Cracking
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
  |
• Lack of metallurgical support of idler tread case hardened layer — Typically new factory idlers; not rewelded idlers • High edge loading • High impact loading • Low abrasive wear • Tight track |
• Crack may continue around idler • Cosmetic cracking — Seldom progresses or propagates deeper into tread |
• Typically cosmetic • Continue to run • Crack will disappear w/ normal wear • Rebuild idler |
Idler Side Wall Weld Cracking
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
  |
• Fabricated idler • High load/impact • Idler tread worn beyond 100% • Fatigue from many rebuilds |
• Structural damage w/ potential idler failure | • Weld/Repair • Replace |
Idler tread Cracking after rebuild
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Lack of proper preheat • Lack of proper post heat |
• Cracks &/or chunks in rebuild idler | • Follow Reconditioning Guidelines — Use heat stick — Proper cool-down after rebuild • Check all idlers before installation on machines • Cracks OK, but not excessive spalling • Watch for crack propagation |
Fabricated Idler Side Plate Damage
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• High impact conditions • Improper/loss of track roller frame guarding |
• Possible fatigue failure • Sealability concerns • Possible shaft bending |
• Small dents/Scratches — Mainly cosmetic • Large dents — Replace lost or damaged guards — Possible idler replacement |
Idler Tread Wear Difference Front to Rear
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Abrasive flow • Unbalanced machine • Tight track |
• Premature idler wear • Improper idler rise height • Can affect fine dozing |
• Balance machine • Proper idler rise height • Add guarding • New Idler Groups • Swap (if possible) • Proper track adjustment • Possible overbuild at rebuild time — Extra weld pass on front idlers — Potential reduction in center flange guiding |
Idler retainer Wear
