This document provides instructions for removing and installing crankshaft main bearings on a Caterpillar C7.1 engine. The procedure involves removing the main bearing caps and shells one pair at a time, keeping each cap and shell together. Thrust washers must be removed from number six main bearing using a crankshaft turning tool. New shells are cleaned and lubricated before installation. Main bearing caps are torqued to specification and end play is checked after installation is complete. A separate section provides instructions for removing the entire crankshaft, which requires first removing other engine components like the oil pump, front housing, rear seal, cylinder head, pistons and connecting rods.