Serpintine belt idler pulley alignment

[dgrasser]

I am having problems with my serpentine belt coming off of the pulleys on a 1998 Dodge Caravan.
It has come off 5 times, usually during rain or snow.
It appears as though the idler pulley is in (toward the engine) to far making the belt ride out on it too far.
Is there supposed to be a washer or shim behind the pulley so it is better aligned?
I just replaced the pulley because is was squealing and I figured the bearings were going out. How do I know if the belt is too tight and is wearing the bearings out prematurely?
What is the best way to loosen the tension pulley without having the secret special tool? I am tired of putting the belt back on the hard way!

[rumblefish360]

The tension should be automatic. Theres a spec some where out there. From what I've read in the past, if the longest length of the belt flexs more than a 1/2 inch, its to much.
Try a pry bar to get the tension off.
As far as alignment goes, try a washer to space it out. Its worth a shot.