2002 ford explorer Belt wobbles on waterpump pully?

I keep having a churp when the truck is running. i took it to a shop and they said that it was my alternator. So i changed the alternator and still had a churp. I also replaced the water pump, water pump pully, Ac compressor, fan clutch, tensioner, idler pully, and several belts, and still have a churp sound when the engine is running. I noticed that where the belt comes off the AC compressor, it goes to the water pump pully. The belt is rocking back and forth on the water pump pully. If i get a long screwdriver, and use it as a guide to keep the belt center on the water pump pully, the churp goes away. From the water pump pully it goes down the the harmonic balancer. How do i adjust to keep that belt from swaying back and forth on the water pump pully. I see no way to adjust,