http://i262.photobucket.com/albums/ii84/jays83/Image013a.jpg
its for the airpump clutch. if you dont want the airpump to operate then just disconnect it and it will behave as a really heavy tensioner bearing.
i found it disconnected so i reconnected it
Only if the air pump motor is working ok. Does the car still have the CAT\'s fitted? If it doesnt then you can leave it disconnected without issue. If you do still have the cat(s) installed then you should have it connected.
Fish