I was doing some rust maintenance in the rear, painted the axle, removed the 9/16" u bolts and brackets, blasted and powder coated them and installed new 5/8" skyjacker u bolts. Torqued in a criss cross pattern according to the link below, snug, then 40 ft-lbs, then 80, then 110. How much do these bolts stretch? Once I hit final torque on the first 2 nuts, the next 2 nuts hit torque sooner than the first 2. Then when I checked the torque on all the nuts they turned a little more before the wrench clicked. Is this normal, it was my first time doing u bolts.

 

http://www.suspensionspecialists.com/techinfo/Ubolt_Information.pdf

When doing u-bolts I tighten them evenly so as to have the same amount of threads protruding from each nut and then once snugged then torque them. What you did is fine and what you felt is totally normal. Remember the u-bolts are basically forming to the shape of the plates and will pull down unevenly as they form, which is why I do it evenly based on length at first instead of torque.

And make sure you check them again after a few days.

And make sure you check them again after a few days.

 

Mmm yes, retorque after a couple hundred miles

I normally play "ring around the rosie" a dozen times.  So yeah, you should be fine.

I would say do as instructed in the document. Then go back in a few days and run the pattern again at final torque setting again.

When I worked at the gear shop I used to make u-bolts, we had a big specialty press bench designed for doing leaf spring and u-bolt work, we custom shaped and arched leaf springs and we carried a full line of all lengths and diameters of u-bolt stock and custom bent them to what ever application one needed, the press had a full selection of different dies for sizes and different bend radiuses or square bends. The shop also carried a full line of about every type and size and hardness of leaf spring stock as well. Seemed we had the older F250 and f350 4X4 Fords with their absolute junk independent front suspension pickups in the shop all the time redoing the front sagged out spring packs.

 

Truth be told I am not sure I have ever torqued but a couple sets of the hundreds I have replaced over the years. Once one knows their air impact well enough and how much torque it puts out on different size fasteners is all I went by as did most other seasoned mechanics but if you don't live with an impact in your hands every day with a torque wrench close by for spot checking then normal torqueing is best.