If axle is UNDER the spring, cut u-bolts off with a torch or sawzall, don't try to save them. They are cheap, along with plates at a spring shop. At least in my area. May need a bigger city for that, or try a big truck repair shop, they have sources. Also check condition of top plate, they sometimes rust bad, unless cast iron. Just don't try to drive or load the truck, and don't knock off the upper spring pack, if it has one. Hardest part is getting the torque high enough when installing. Ask the shop for torque setting if you don't have a manual with specs. The new U-bolts maybe longer, I just leave the extra on, or can be cut once installed. Don't forget the extra tall nuts and washers for them too.
