Before removal of the crankshaft, the drive plate, the crankshaft pulley, and piston assemblies should be first removed. The endplay of the crankshaft is checked before loosening and removing the bolts that holds main bearing cap. Thereafter, the crankshaft is lifted off from the engine. Using Plastigage on main bearing oil clearance and lubricating through main bearing caps are some of these checks. Finally, you can check again to ensure that there is a correct endplay in the crankshaft then install a new rear main oil seal.