Remove the timing belt. You take off the crankshaft sprocket from the crankshaft, and the inner belt guide, then remove it so the curved edge faces away from the timing belt. Using a seal removal tool, or a screwdriver, pry the seal out of the oil pump housing, being careful not to nick or scratch the crankshaft or oil pump housing which could result in leaks with the new seal. Clean bore in oil pump housing and coat outer edge of new seal with engine oil or multi purpose grease. To drive in a socket with a slightly smaller outside diameter than the seal with a hammer, or, in the alternative, a short section of large diameter pipe can be used. Check the seal following installation to make sure the spring didn't pop out. Put the timing belt on the crankshaft sprocket and the inner belt guide, then reinstall the crankshaft sprocket, reworking through the inner belt guide. The crankshaft pulley sleeve should also be lubricated directly with engine oil or multi-purpose grease before installation. Last, run the engine, looking for leaks.