1. Remove the toothed belt and crankshaft pulley.
2. Using a screwdriver, the blade of which is wrapped with adhesive tape, remove the crankshaft sealing ring from its socket. Be careful not to damage the O-ring seat and the crankshaft.
3. To facilitate the removal of the O-ring, a hole can be cut in the end surface of the O-ring.
4. Clean the O-ring seat and lubricate the new O-ring with clean engine oil.
5. Using a tubular drift of the correct diameter, install the O-ring on the crankshaft.