Loosen and remove nut from the lower alternator securing bolt. Do not remove the bolt yet.
The alternator is now loose on the 3 securing bolts. You should now slacken off the 8mm adjusting bolt, shown here on a removed engine (no way to get the camera in on the car). This is best done from above by feel (you cannot see it) or from underneath the car.
Now remove the belt, remove the lower securing bolt from the alternator, and the adjuster bracket should now swivel down, free of the alternator.
You should now disconnect the main live cable, which is held on by a 13mm nut which is held captive on the cable crimp, so you cannot drop or lose it. Also dissengage and remove the plug at the top.
You now need to take the weight of the alternator and withdraw the top securing bolt. Warning...Once you remove this bolt the alternator could drop. In my case the alternator was still wedged in and needed a bit of waggling and levering before it came free. Now remove upwards and out.
Here you can see the loom with the two connections in. There are actually 3 connections as there are 2 in the plug. One is for the battery warning light, the other (I assume) is a live battery feed for excitation of the alternator. The battery warning light circuit is fed from fuse 25 in the fuse panel under the steering wheel. The excitation feed comes from god only knows where, as it isn't even shown on my circuit diagrams.
Here is the new alternator (Mmmm, shiny). It did come with a new pulley fitted. A bit annoying as it took me ages to take the old pulley off so that I could exchange the alternator. It didn't come with the 8mm adjuster bolt, so remove that and keep if you are planning on going the exchange route.
Refitting is the reverse of removing. Lower the new alternator in place and refit the upper securing bolt. Screw on the nut but do not fully tighten at this point. Reconnect the electrical connections (a bit of copper grease on the nuts and bolts will help on removal and rust resistance)
Clip the lower bracket back over the 8mm adjuster screw and refit the lower bolt through the alternator, so that it protudes through the slot in the bracket. Refit the nut, but do not tighten at this stage.
Refit the belt and ensure that it is sitting correctly on both pulleys. Now tighten the 8mm adjuster screw until the correct tension is felt on the belt. I went for a couple of mm's movement up/down at the longest point. You can also twist the belt to get a feeling of how tight it is. There is probably a correct figure somewhere, but I have done a few belts in my time and tend to go by feel, which is difficult to put in words. Overtightening can cause more problems than undertightening, as you are putting a greater load on the bearings.
Once the belt is at a correct tension you can tighten the 3 alternator securing bolts. The upper bolt
The engine securing bolt
And the bottom alternator securing bolt
Your alternator is now fitted. Now to put the car back together. Don't forget to put the plastic cover back in the wheel arch.