I've got a noise coming from the alternator pulley and was wondering what the best solution would be regards repair. 1st option is a new pulley at around £63 fitted 2nd is a new alternator at around £260 + labour. The original alternator has done 87k. Removal doesn't look an easy job and even getting the pulley removal tool in to remove the pulley looks too tight tbh.

I'd just replace the pulley in this case.

If you're sure that the noise is from the pulley and not the front alternator bearing, then I'd just change the pulley. Modern alternators are electrically very reliable, no brushes to wear out or voltage regulators to burn out. Occasionally the 3 phase rectifier pack fails but that's about all.

3 hours ago, unofix said:

no ... voltage regulators to burn out

To be pedantic conventional alternators do have an internal solid state regulator circuit, normally packaged with the rectifier pack, to maintain the output voltage to 14.4V or so by adjusting the alternator field current. More modern alternators still include similar circuitry to determine the output voltage but this is controlled by an external input signal from one of the cars computers to reduce the output voltage, and hence engine load, when the full output is not needed. This is in the name of producing a marginal reduction in  emissions. Oh for the simple days!

Oh for the simple days, dynamo and external regulator. Or am I going to far back now. 

I've been to the see the mechanic this morning and he's diagnosed the bearings failing/failed on the alternator so it's booked in for a replacement.Thanks all for your feedback 👍 

1 hour ago, iantt said:

Or am I going to far back now

Yes, though I do remember such things. A non-electronic 'buzzer' box to regulate the dynamo output by breaking the field current with a pair of contacts that opened when the dynamo voltage was too high. Youngsters will have no idea what I am talking about!

I remember that system too. The relay also incorporated a few turns of heavy gauge wire in series with the dynamo to add a degree of current regulation.