Leaf Spring U-Bolts

One of the unsung heroes of any leaf spring suspension upgrade, the humble leaf spring U-bolt has a very important job. The U-bolt keeps the leaf spring secure to the axle, ensuring proper axle position and maintaining the right suspension geometry and driveline angles.

Yet it’s easy to overlook the need for replacing or upgrading the leaf spring U-bolts in your suspension system. Unless of course, you’re running a modified suspension or non-stock front or rear axle. In those cases, you may need longer or wider leaf spring U-bolts to fit. For instance, adding lift blocks or lowering blocks to your axle could demand 4-inch, 8-inch or even longer leaf spring U-bolts. That’s because the U-bolt will have to compensate for the block, demanding extra length on the leaf spring U-bolt, so you still have enough thread length to secure the U-bolt nuts.

But even if you’re not adding lowering or lift blocks, running an aftermarket spring pack may require longer leaf spring U-bolts too, particularly if the spring pack features additional leaf or helper springs. Additional springs can increase the overall width of the spring pack, meaning that you may be unable to reuse the stock leaf spring U-bolts. So, if you’re upgrading leaf springs, take some measurements to determine if you’ll need new leaf spring U-bolts and, if so, how much longer those U-bolts need to be to complete your leaf spring installation.

If you’re simply swapping out stock parts for new ones, replacing your original leaf spring U-bolts may not be a bad idea either. Given their position on the vehicle, the threads on the end of your front or rear axle U-bolts are often exposed to the worst of what the road has to offer. Mud, salt, large rocks—there are plenty of road hazards that can severely damage your leaf spring U-bolt threads, or bend and distort the ends of the U-bolts entirely. Even up top where they wrap around the axle, your leaf spring U-bolts may be worn, corroded, or otherwise degraded to the point where you’ll need to replace them.

Standard or long, front or rear axle, whatever leaf spring U-bolts you need for your ride, you’ll find them right here, at Summit Racing.