I've decided I'm going to remove the u-bolts and replace them with the correct ones (nuts as well). But here's my problem. I currently have 4 degree wedges under the axle. They're about 1/2 inch thick at their thickest end, which doesn't allow the pin in the leaf spring to go down into the hole in the axle. I put these in on the advice of another forum member because I was having a problem with seriously uneven front end height when I installed the new springs. The 4 degree wedges fixed most of that problem. Don't know why, but they did. Anyway, if the wedges are too thick to allow the u-bolt pin to go into its hole, should I go to thinner wedges? Is there a way around this? The truck rides well with the wedges now. Also, I've always worried that since the pins are most likely not in their holes that the axle may have moved some and may never have been centered at all. If I get the pins in the holes on both sides, doesn't this automatically mean that the axle is positioned correctly under the truck?
You need to remove everything that you have and go back to original design parts. Those "wedges" are designed to set your caster, not adjust ride height. They are called cater shims.
For u-bolts, take some originals with you to a spring shop and have new ones made. They will come with the correct nuts.