To replace the front seal the timing chain cover has to be supported on wooden blocks and the seal has to be driven out using a punch and hammer. Make sure that the seal bore won't have nicks or burrs on its surface and apply some engine oil on the seal lip and the outer ring. This should be placed in such a way that its lip goes round the pipe's inner side, and it is driven in with the help of a seal driver, or a large socket or a piece of pipe of the same diameter as the seals if a seal driver is not available. For the rear seal, one has to dismantle the transmission, clutch if fitted and the flywheel or drive plate together with the engine rear plate. Insert two holes on the seal, two sides of it near the main bearing cap, then screw in each of them two sheet metal screws. With large screwdrivers or small pry bars pry against the screws to remove the seal being cautious not to scratch the crankshaft. Debris the oil seal bore and see if there are any nicks or burrs; apply thin coat of clean engine oil on outer periphery of the seal and the bottom. Next arrange the seal in the bore with its open end directed towards the centre and driving it into place with the seal installer until properly home; a socket or pipe may be necessary. If no seal driver is possible, knock the seal gently with a hammer and a drift to get it into position perpendicular to the centre line of the crankshaft or within the required dimensions.