Description The 9–10K U-Bolt Kit fits heavy trailer axles with 4″ round axle tubes used on 9,000 lb and 10,000 lb capacity trailers. This kit suits trailers that use 2.5″ wide leaf springs, a common spring width for higher capacity tandem axles and general duty applications. The U-bolts and associated plates clamp the axle to the leaf spring stack and spring seat for a solid suspension mount. This U-bolt kit includes four 5/8″ diameter U-bolts, spring plates, and matching nuts and washers. The typical U-bolts measure roughly 8″ long with legs spaced to wrap around a 4″ diameter axle tube. You install this axle U-bolt kit after you align the springs under the axle tube. Slide the U-bolts over the axle tube and through the spring plate holes. Then put the tie plates under the leaf spring stack. Thread the nuts on and tighten them gradually. Proper torque helps keep the axle centered and stable under load on the highway or jobsite. This kit works on trailers with leaf spring suspension systems that use double-eye or slipper springs rated for 9K–10K GVWR. It works on equipment trailers, gooseneck trailers with matching capacity, livestock trailers, and heavy utility trailers. Match the U-bolt kit to your axle tube diameter and spring width for safe, reliable service. Use this U-bolt set for axle rebuilds, spring replacement jobs, or suspension upgrades. New U-bolts and plates keep your trailer aligned and quiet. They also prevent axle shifting that leads to uneven tire wear and poor handling.