When do you need to replace leaf spring center bolts?
For most leaf springs the center pin will never need to be replaced, but there are a few situations that will require the pin to be replaced.
Center bolt breakage due to impact accident – Leaf spring center bolts can break under the right conditions. An accident where the axle is struck can put enough force on the center bolts to break them and allow the axle to shift. In an accident, there may be more damage to contend with than just a broken center bolt, so the entire suspension should be inspected thoroughly.
Center bolt breakage due to loosened U-bolts – Loose leaf spring u-bolts can transfer additional stress to the leaf spring center pins and cause them to break. When this occurs, the leaf spring pack may shift and no longer be in alignment. Leaves may turn and stick out from the leaf pack which was a neat stack before. The axle may cause dog tracking as the centering pin is no longer centered in the axle. In these cases, the center bolt and the U-bolts should be changed.
Adding leaves to spring pack – When adding additional leaves to a spring pack you may need a longer center bolt to tie the entire pack together.
Replacing a leaf – If a leaf has broken you will need to remove the center pin for pack disassembly, and in most cases, the center pin will need to be replaced.
Replacing overload spring – Some overload springs will be tied to the main spring pack using the center bolt. When replacing these upper contact overload leaves the pin should be replaced to ensure its strength.