Leaf Spring Fastener Center Bolts

Center bolts and nuts are a type of fastener that has two components—the bolt itself, which is typically made of steel or another metal alloy, and the nut, which is usually made of plastic or metal. The bolt has a head on one end that's threaded so it can accept the nut. The nut has an interior thread that screws onto the bolt’s exterior thread. When the nut is fully tightened onto the bolt, it creates a secure hold between the two pieces. Center bolts and nuts have many uses in various industries. In automotive applications for attaching features like brakes or exhaust systems; In each application, center bolts and nuts provide a strong connection between two parts while still allowing them to move independently if needed. In a leaf spring assembly, one of the most important pieces is the center bolt. At the center of each leaf is a hole. The bolt gets slotted through this hole in each of the four, five or more leaves that comprise a spring. Effectively, the center bolt holds the leaves together and puts them in contact with the axle. The center bolt head connects to the axle, which gives the truck its rear suspension in combination with the leaf springs. Despite its importance, the center bolt is also one of the most potentially vulnerable parts of a leaf spring. Ensuring the center bolt does not break due to the flexing of leaves requires another component to keep the leaves bound tightly together in the form of a spring assembly. For this purpose, U-bolts bind leaf springs together. On each side of the center bolt, U-bolts clamp the leaves into a tight spring. The center bolt relies on the U-bolts and vice versa to maintain solid leaf springs on both sides of the rear axle of a truck. Consequently, if the U-bolts are too loose, the center bolt could eventually break due to pressure from the flexing leaves. For the U-bolts to do their job properly, the right amount of torque specs need to fasten them. This spares the leaf spring from troublesome movements that could damage the leaves, the axle and especially the center bolt. On trucks where the U-bolts are not sufficiently fastened, the damage typically occurs in the following order — first the center bolt breaks, then the individual leaves of the spring give way more rapidly due to cracks caused by flexing motions each leaf makes against the surface of its neighbor. Leaf spring center bolt removal can be tricky or easy, depending on the type of grip you manage to get on the pin. While it can come in handy to know how to remove the center pin from a leaf spring, you might find it best to replace the leaf spring entirely.