Sounds like you have lost the rubber bushing, or bushings, that should isolate the pivot pin / bolt and the piece held to the springs by the u-bolts.
Check your shop manual for a picture, page 4-61.
You should be able to see if there is anything there by looking to see if the bolt is centered in the big hole, or sitting on the top edge of the hole.
Or, jack up each side by the bottom of the spring and see if the springs moves before the axle does, or at the same time.
