I have a SCAT Serpentine belt setup which is only fairly new. A couple days ago I've noticed I can hear a knocking sound, but when I took the belt off it disappeared. I did some checking on how everything is secured and I just put the belt back on and the sound is still there. But I think I found the issue.....
The groove in the pulley that slides over the key seems to have got quite a bit larger and the pulley is can now move on the shaft. I've included pics of the pulley and the damage to the key.
Has anyone seen this happen before? Any ideas on how to rectify the issue, short of buying new parts?