Q: The friends we travel with just had a shackle bolt fail on their fifth wheel trailer and it could have been pretty catastrophic. The mobile repair guy installed a new bolt and shackle and told us we both should look into "wet bolts" What are these?
�� Don
A: Shackles and bolts attach the leaf springs of a trailer to the frame. Shackles are short metal plates with a bolt hole at each end that connects one end of the leaf spring either to an equalizer (tandem axles) or the frame. The bolts and shackle work together to allow a pivoting action so the leaf spring can change length as it compresses and rebounds. Leaf spring eyes are larger in diameter than the bolts, allowing a bushing to be used to mitigate friction. Original equipment bushings are typically nylon. In time the bushing wears, the holes in the shackles can elongate and the bolts may wear thinner and potentially fail.
Wet bolts are shackle bolts with a small internal passage and a Zerk fitting threaded into the bolt head. A bronze bushing is used instead of the nylon, and the assembly can be lubricated using a grease gun. This is a big improvement in friction reduction, and long-lasting, as long as the bolt is of high quality. If renewing these parts it's not a bad idea to upgrade the shackles to thicker/beefier versions and remember to apply lubricant periodically. I would go with parts sold by a company such as E-trailer rather than looking for something inexpensive on Amazon.
