Remove toothed belt - see operation "Toothed Belt, Remove and Install (17 D)" or "Toothed Belt, Remove and Install (17 DR and X 17 DTL)". Remove camshaft pulley (2) from camshaft - counterhold with open-ended spanner (1) at hex of camshaft. Edge out seal ring (3) with suitable tool - ensure that sealing surfaces are not damaged.
 Install, Connect Coat sealing lip of the new seal ring lightly with silicon grease (white) and press into camshaft housing with KM-422 - use bolt and washer of the camshaft pulley. Install camshaft sprocket with new fastening bolt on camshaft - fastening nut should be hand-tightened only. Install toothed belt - see operation "Toothed Belt, Remove and Install (17 D)" or "Toothed Belt, Remove and Install (17 DR and X 17 DTL)". | 
Remove, Disconnect 