When I had my cambelt changed recently the mechanic took of what he called the front pully.

He said it was corroded and wasn't necessary as it only drives the A/C or power steering, of which I have neither

(Rev1 Mk2 NA).

If it is the same one as your refering to its internal diameter is apprx.115.5mm and external

(to the outer lip) is apprx 144mm.

If you need any more info or photos to confirm its actually the correct pully, let me know.
