CATBearing & Bushing

1N4321 Main Bearing — Cat Engine: D353

This main bearing is a critical component of the engine's rotating assembly, providing a low-friction surface for the crankshaft to rotate within the engine block. It is manufactured to meet stringent OEM specifications, ensuring superior durability and performance compared to a worn bearing that exhibits scoring or excessive clearance. Operators may notice a knocking or rattling sound from the engine, particularly under load, which can escalate to reduced oil pressure and potential engine seizure if left unaddressed.

Main Bearing – Part No 1N4321 – CAT Spare Part
Part Specifications
BrandCAT
CategoryBearing & Bushing
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

Never strike bearings directly — use a bearing press or driver set. Heat housing (not bearing) to ease installation. Replace bearings in sets where applicable. Check housing bore diameter before fitting — out-of-round bores destroy new bearings.

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

Part TypeEngine Main Bearing
MaterialSteel-backed babbitt lining
ApplicationEngine crankshaft support
Service LifeReplace based on engine overhaul schedule
CompatibilityOEM specification
ConditionNew — OEM specification aftermarket

Failure Symptoms

Initial signs of main bearing failure may include a persistent knocking sound from the engine, especially when accelerating. If ignored, this noise will likely intensify, and oil pressure may begin to drop, indicating increased clearance. Continued operation risks severe crankshaft and block damage, potentially leading to engine failure.

Installation Tip

Ensure the crankshaft journals and the bearing bores in the engine block are meticulously clean before installation. Avoid using excessive force when seating the bearings, as this can damage the delicate lining.

Service Note

Inspect the crankshaft journals for scoring or wear, and check the connecting rod bearings for signs of damage during main bearing replacement.