I'm about to change my timing belt and waterpump on my 2002 A4 B6 1.9 TDI Avant, I've watched a few youtube videos on doing this but have a question about the camshaft pulley, I noticed that the three bolts with adjustable slots have to be loosened to get the belt off but what happens when putting it back together and putting the tension on the belt, does it have to be put back exactly where it was, do I need to mark the position before loosening the bolts, the reason I'm asking is that I'm thinking the wrong position might affect the cam timing, I've done loads of timing belts over the years but not one on the 1.9 TDI PD, any thoughts on this please