CATUndercarriage

420-9805 Rear Idler — Cat 239D 249D

This Rear Idler is a crucial component of the undercarriage system, designed to guide and support the track, maintaining proper tension and alignment. It is manufactured to meet stringent OEM quality standards, providing superior durability and wear resistance compared to a worn or damaged idler. Operators may notice increased track noise, excessive vibration, or premature wear on the track pads when this rear idler begins to fail.

Rear Idler – Part No 420-9805 – CAT Spare Part
Part Specifications
BrandCAT
CategoryUndercarriage
ConditionAftermarket — OEM Specification
DispatchSame-day from Mumbai (before 3 PM IST)
GST InvoiceAvailable — all orders
Export DocsCommercial invoice, packing list, COO

Compatible Models

Always verify with serial number before ordering.

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Installation & Application Notes

Cross-reference part number with serial number before ordering to confirm fitment. Keep original parts until new ones are confirmed correct. Record part numbers replaced for future reference.

Always consult the OEM service manual for model-specific torque values and procedures. WhatsApp our technical team if you need fitment guidance.

Part TypeRear Idler
MaterialForged Steel
ApplicationUndercarriage System
Service LifeReplace as needed based on wear inspection
CompatibilityOEM specification
ConditionNew — OEM specification aftermarket

Failure Symptoms

Early signs of a failing rear idler include unusual noises, such as grinding or squealing, and increased vibration during operation. If left unaddressed, this can lead to accelerated wear on the track system and potential track misalignment. Continued operation with a faulty idler risks track derailment, causing significant downtime and repair costs.

Installation Tip

Clean the mounting surfaces thoroughly before installing the new idler to ensure proper seating and prevent premature wear. Avoid overtightening the mounting bolts, as this can damage the idler or the mounting bracket.

Service Note

When replacing the rear idler, inspect the track chain, rollers, and drive sprockets for wear and proper alignment.