Replacing the front camshaft seals of a 16-valve engine (Opel Kadett E)

Remove the timing belt as described above.

Remove the cylinder head cover and the parts installed on it.

Lock the camshafts one by one by placing a wrench on the Allen key on the flange of the camshaft, unscrew the bolts securing the camshaft pulleys and remove the pulleys.

Punch a hole in the seal housing using a square-head punch, first inserting a piece of cardboard under the sealing edge of the seal to avoid damaging the camshaft journal.

Screw a self-tapping screw into the punched hole and press out the seal by pulling the screw with pliers.

Clean the surface of the shaft journal, being careful not to scratch it.

Press a new oil seal onto the shaft using the KM 422 tool.

Install the camshaft pulleys so that the pins and timing marks are facing up.

Tighten and tighten the camshaft pulley mounting bolts to a torque of 5.0 kgf·m, then turn them by 60-75°, holding the shafts by the hexagon with a wrench

Install previously removed parts in the reverse order of removal.

Place the timing belt on the pulleys and adjust its tension as described above.