Tensioning Alternator Belt - help please

Hi,

I want to tighten up my alt belt a little. Do I just give the adjuster ‘worm’ screw a tighten or do I need to loosen the bolt on the holding bracket first?

Any help gratefully received. Death to the mouse (the one that only squeeks when I have the lights on!!).

 You need to loosen two bolts before using the adjuster screw. One below the alternator where it swivels as you adjust, and the other (very awkward to get at!) behind the adjuster assembly.