[jeffreyb4me]

Do NOT loosen the tensioner bolts ! ! The tensioner is 'fixed by it's mounting bolts, the spring is ONLY there to pre-tension the belt @ new installation time, used belts MUST NOT be 're-tensioned' ! !

now, you need to grab the end of that pin and pull it away from the waterpump as far as you can [ compressing the spring completely ]. The pin will be moving towards the alternator. Now for the fun part...while your holding the pin with one hand, you need to 'lock' it with the other [ not much room ].....I recommend using 2 small needle nose 'vise-grip's, they work very well for me. Note that the "proper" factory tool was only a small block with a thumb screw that fit over the pin and lock it. BMW left up to you to figure out how to pull on the pin and the 'tool' took up most of the end of the pin. I haven't seen mine in 20 years but haven't missed it.

hope this helps and best to you.......................................jeff b.