Halfway through the job of replacing the Crankshaft front oil seal on my 3 bearing series petrol motor. Its not difficult but it is time consuming. The only point I wish to make is regarding the sump gasket upon renewal. Look for the thickest you can find because they do vary in thickness depending on the supplier. You need a good thick 'un on account of spot weld marks on the contact face that secure the retaining flange underneath.