Rear Drums.... Click

Could possibly be the Emergency brake. E brake doesn't use a caliper to ingauge. You can tell because when you pull the e brake it makes a clicking noise. (higher the more brake applied to the rear drums.) I would take off the wheels and drums. Then try spinning the actual drive line to see if anythings out of the ordinary. Sounds like somethings broke and is rubbing when its dry. Makes sense when its raining, due to less friction.

John

Are you sure it's not a U-joint or bad bushings in your control arms?

I have a similiar problem I am curious as to what you find!