Idlers for Mini Excavator
CAT 305.5 Idlers
Replacement idlers for CAT 305.5 mini excavators. Guide the track and maintain proper tension. Wholesale pricing with fast shipping from our Houston warehouse.
Researched Part Numbers for CAT 305.5
Research-Based Fitment Data: The following part numbers have been researched for compatibility with CAT 305.5 mini excavators. Part numbers and fitment vary by serial number range.Please call 346-438-6252 with your machine serial number to confirm exact fitment before ordering.
Research-Based Fitment — Call to Confirm
267-4813
front idler
CAT 305 / 305.5 Tension Idler 267-4813
Primary Part Number
267-4813
Supersession / Interchange Notes
Older 304.5/305.5 used tension idler 240-6304.
Compatible Machines
Caterpillar 305E2, 305.5E2, 305C CR, 305D CR, 305E mini excavators (front/tension idler).
Mount Type / Chassis Notes
Front/tension idler for the 305/305.5 undercarriage. The 305/305.5 uses a single tension-idler design (no separate rear idler part). Older 304.5/305.5 machines used 240-6304.
Serial Number Specific
Verify serial - older 304.5/305.5 used 240-6304.
Research-based fitment data. Please call with your machine serial number to confirm compatibility before ordering. Part numbers and fitment may vary by serial range.
346-438-6252 • Houston, TX
About Track Idlers for CAT 305.5
The idler is positioned at the front of the undercarriage, opposite the drive sprocket. It guides the track around the front of the machine and maintains track alignment. The idler also absorbs shock loads when the machine encounters obstacles or uneven terrain.
Idlers contain sealed bearings similar to bottom rollers but are designed to handle higher loads and maintain track alignment under varying terrain conditions. The idler shell may feature single, double, or triple flanges depending on machine design.
The idler assembly includes the track adjuster mechanism, which uses hydraulic or mechanical pressure to maintain proper track tension. Correct tension is critical - too loose causes derailment risk, too tight accelerates wear on all undercarriage components.
How Track Idlers Work
The idler rotates freely on bearings as the track moves around it. Spring or hydraulic pressure pushes the idler forward to maintain track tension. The idler flanges guide the track laterally, preventing it from walking off the undercarriage. On uneven terrain, the idler absorbs impact and allows the track adjuster to compensate for variations.
Signs You May Need a Replacement Idler
Idler problems affect track tension, alignment, and overall undercarriage performance. Watch for these indicators:
•Track Wandering or Walking Off
If the track consistently drifts to one side or tends to walk off the undercarriage, the idler may have worn flanges or internal damage affecting alignment.
•Uneven Idler Surface Wear
Inspect the idler shell for flat spots, grooves, or uneven wear patterns. These indicate bearing problems or misalignment that will worsen if not addressed.
•Noisy Operation or Grinding Sounds
Squealing, grinding, or rumbling from the front of the undercarriage often indicates idler bearing wear or seal failure.
•Track Tension Problems
If track tension cannot be maintained or the track seems loose even after adjustment, the idler or adjuster mechanism may be damaged.
•Leaking Seals
Oil or grease weeping from around the idler indicates seal failure. Contamination will quickly destroy the bearings.
•Wobbling or Excessive Movement
Side-to-side wobble when rotating the idler suggests bearing wear. This affects track guidance and will cause premature track wear.
Fitment Verification
Idler specifications vary significantly by machine model and serial number. Flange configuration (single, double, or triple), shaft dimensions, and overall size must match exactly.
Some machines require specific idler variants based on undercarriage configuration or production changes. Always verify with your serial number.
Contact us with your machine details, and we will confirm the correct idler specifications including flange style and dimensions.
Free Fitment Verification
Not sure which idler fits your CAT 305.5? Contact us with your serial number and we will verify the correct part at no charge.
Related CAT 305.5 Parts
Complete your undercarriage maintenance with these related components for your CAT 305.5.
Get a Quote for CAT 305.5 Idlers
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Frequently Asked Questions About CAT 305.5 Idlers
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