The crankshaft in most cases can only be removed from an engine when the engine is detached from a car and additional parts that include the flywheel, crankshaft pulley, timing chain, oil pan, oil pump, oil filter, and piston/connecting rod have been removed. To take the crankshaft endplay, place a dial gauge on the crankshaft in line with the centreline of the cylinder block. With the crankshaft turned to the rear tighten the hold down, turn the crankshaft to the extent of movement SET indicator dial and then turn the crankshaft to the front to get the READING which should be between 0.003 to 0.010 inch. Feeler gauges can be used in case one doesn't have the dial indicator in checking for clearance. Slacken off the main bearing cap bolts while they can still be undone by hand and then use a soft-faced hammer to tap the assembly up and thereby lift it off the block in this position without bending the bearing inserts. Withdraw the crankshaft slowly, if at all possible, with help and replace the main bearing cap assembly with the arrow aimed forwards. For installation you must make sure the engine block and the crankshaft must be cleaned and checked. The main bearing cap assembly and original bearing inserts should be taken off and the surfaces cleaned. Install new upper main bearing inserts into the block; oil holes must conform and install lower inserts to cap. Measuring the oil clearance of the main bearing with the help of Plastigage and comparing it with standard values if necessary. If clearance is not correct then make sure that the bearing is clean and then if required decide between the size of the bearing to be used. After cleaning Plastigage residue, apply a coat of grease on the bearing areas and the thrust faces and replace the crank shaft and the bearing caps if necessary and seal them where necessary. Secure the bolts to the recommended torque, redial crankshaft end play, and crank shaft should rotate easily with least resistance. Last but not the least the installation of the new rear main oil seal.