This what we have so far. The spring is hung from the frame. The yellow strap is to help pull the axle forward in to position. I did one side at a time, so there was still some tension from the old spring on the other side. There is a hole in the spring pad on the axle that matches a stud on the bottom of the spring. Make sure that these line up.
Next you are going to attach the axle to the springs. The bumpstop has to go on top of the axle first, it sits on the bolt sticking throught the spring pack in the picture above. The bolt is longer than the hole in the bumpstop is deep, so you will have to drill out the bumpstop a bit to get it to fit. You will be drilling into rubber, so it is not too tough. Place the modified bumpstop onto the spring and the new u-bolts over top of it.
Underneath the axle and spring, put some Loctite on the U-bolt threads and install the plate and four nuts. The stud on the plate faces inward, this is where the shock absorber mounts.
leave the u-bolts a bit loose. Once you get both sides installed, make sure that the axle is square to the frame of the truck. Take measurements from each side to a crossmember on the frame to ensure this. Once everything is OK, go ahead and tighten down the u-bolts.
The last parts to go on are the shock absorbers. You will have to greas and install the bushings on the shock eyes. They go on just like the old ones came off. The writing on the shock should be right side up, at least with the OME's that I have.
Do not forget to install your brake line.
You now have this:
You can go ahead and put the wheels back on it and take it off the stands.
Before you do anything else, go back through the entire truck and recheck every bolt that you touched to make sure that they are properly tightened. Then you can go and return the spare it it's perch under the bed. Don't forget to get the front end aligned, you will need it.
After you drive the truck for about a week, you will need to go back and hit the grease fittings on the rear shackles and UCA's. Give them each a shot or two of grease, but be careful not to blow out the bushings. You should also re-check all of the fasteners at this time to make sure that nothing came loose.
Here is the old junk that came off of my truck: