To get to the crankshaft, it may have to be removed along with the engine, with conditions that the flywheel, crankshaft pulley, timing chain, oil pan, oil pump, oil filter, and the piston/connecting rod assembly have been already taken out. To start with, the crankshaft end play is established by placing a dial indicator against the crankshaft. Loosen the crankshaft at the rear and set the indicator to zero then push the crankshaft towards the front to the reading which should be between 0.003 to 0.010 inch (0.076 to 0.254mm). If the endplay is greater than this range, the thrust washer/ bearing assembly surfaces should be checked for wear. If none of the wear is detected, new main bearings can do the trick. In case an access to a dial indicator is impossible feeler gauges could be employed for indicating clearance. Unthread the main bearing cap/bedplate bolts gradually and remove them until they can be taken off with bare hands, while gently hammering on the assembly gently and lifting it off the cylinder block without dropping the bearing inserts. It is a fairly heavy component and may require you to lift it since it is usually submerged into the engine; get some help in case of lifted situations. When the bearing inserts have been installed, the main bearing cap assembly will have to be put back on the engine block accompanying the arrow oriented towards the front. When installing the crankshaft some of the important points that have to be followed are: Align the block with the bottom up, lift of the main bearing cap assembly, and clean the bearing seat surfaces. During the assembly, fit new upper and lower main bearing inserts with due consideration to the oil holes' orientation and uniformity for the bearing faces. Ensure that the oil ways in the crankshaft are clear, place/lay the crankshaft in position, lubricate and install the correct thrust washers. When the unit is still temporary, measure the oil clearance of the main bearing with the Plastigage and make sure that it falls into the correct range. If the clearance is wrong, check cleanliness and in case of the bearing inserts think of other ones. Once again remove any Plastigage residue and put the crankshaft back into its place, clean the faces of both the bearing insert and apply a low thickness of oil on it and finally place the crankshaft. Scrub the two bearing insert faces, then lubricate them; place the thrust washers of the crowned type with their recessed sides outward. When tightening the main bearing cap bolts ensure that they are new bolts and that the torque setting is correct The engine oil used should be clean and it should be used to coat bolt threads before they are installed. Check crankshaft end play again with feelings and turn the crankshaft with hands to see if there is any tightness, looseness or binding. Last of all, fit the new rear main oil seal.
Posted by NissanPartsDeal Specialist 
