Caterpillar Incorporated 1N-4322 Main Bearing

Caterpillar 1N-4322 is a main bearing insert, sold as a 0.050-inch undersize option for Caterpillar diesel engines such as the D353 and G353D (and related models). The part is designed to support the crankshaft main journal and maintain proper oil clearance during operation. The outer diameter is 127.61 mm (5.02 in), enabling a precise fit within the crankcase bore. CAT lists 1N-4322 as a main bearing with the size 0.050 in and notes its applicability to D353 and G353D engines, making it a standard choice during overhaul when the journals are undersize or when restoring proper clearance after wear. The bearing is offered in steel-backed copper-lead composition, with some production runs using a steel-backed aluminum bearing, reflecting Caterpillar’s material selection for wear resistance and load distribution. This undersize bearing is typically used in conjunction with other Caterpillar engine bearings during overhaul to restore original clearances and extend engine life. Verified retailer catalogs and replacement-part listings consistently associate 1N-4322 with D353/G353D engines and document the 0.050-inch undersize specification, underscoring its role in precise crankshaft support within the engine’s bottom end.