To replace the oil pump housing oil seal, first remove the oil pump, then using the appropriate tool drive the oil seal out from behind but do not damage the housing. Remove the burrs and sharp edges likely to be present near the seal housing and crankshaft contacting surfaces. Apply grease to the lips and periphery of the new seal, and perhaps it's beneficial to employ a service tool to pull it into position. As with the earlier seal lips, it is very advisable to avoid the seal lips from catching on the crankshaft, this can be done by using a plastic tube to feed the seal into a correct position. It is usually possible to seat the seal with hand pressure, although use of a socket may sometimes be required. Casting off is done in the reverse order, with the possibility of oil leakage tested in the process when starting up the engine. In the case of the flywheel end oil seal, one has to first take off the transmission and clutch assembly, then take off the bolts holding the flywheel and oil pan. Take off the oil seal carrier and dispose of the gasket, and push out the new oil seal from behind, do not forget to clean the housing and crankshaft as well. Lay the carrier in a new gasket also inspect the alignment with feeler gauges and then tighten the bolts to the recommended torque. If the carrier is misaligned, do same process in the exact procedures followed above. Original seal should be replaced with a new one, service tool or homemade guide must be used to lubricate the lips and to insert the new seal properly. Remove the residue oil or grease and reassemble, examine for oil leakage when the engine is again started.