alternator pulley alignment

I have an 86 VW Jetta Diesel. The original pulley is shot and I go through a belt once a week. I looked online and ordered the OEM replacement pulley but it looks different. The notes said:30mm Extension Converts AL---X to AL---M type alternators.

Please help!

I think your best (and cheapest) bet is to hit a junkyard. Just buy the whole alternator for $5 and swap pulleys. You can even find VW-only yards that ship. Have them locate a pulley and send it to you for $10

Thanks for the idea, I found an alternator repair store and they gave me a good condition pulley and replaced it for free.