[Mr Teddy Bear]

The git seal can wear a ridge or mark into the seal surface of the shaft. We used to experience this problem with the out put drive flange on big commercial gearbox's, the laborious first answer was fine wet and dry and polish out the wear mark on the flange seal surface. Then fit a new seal and lubricate the seal lip with oil before fitting. This used to work I should add, as we tested the box's on a couple of test rigs.

There are lot's of glitches involved in changing the camshaft's because you need to change the cam followers too.