as someone that works in a autoparts store i can tell u that the metal one workk a HELL of a lot better, if u can get to a parts store u should be able to show them what u have and then they could mach it up, the best thing about a metal pully is that all u need to fix it is a 203ff baering with here in the stats is $4.00. if u cant find it let me know and ill give it a go.

good luck