A direct-replacement shoulder bolt for Lippert-compatible trailer leaf spring, shackle, and axle hanger assemblies. Match your original hardware dimensions before ordering -- body diameter, shoulder length, and thread size must all align for a safe, correct fit.
The Lippert 271254 is a precision shoulder bolt engineered for use in RV trailer suspension systems that use leaf springs, shackle links, and axle hangers. Unlike a standard hex bolt, a shoulder bolt provides a smooth, unthreaded body section that acts as a pivot or bearing surface -- critical in suspension applications where components articulate under load.
With a 9/16" body diameter, 2.825" shoulder length, and a 7/16"-20 fine-thread end, this bolt is dimensionally specific. It is not a universal fastener. Verify all three measurements against your existing hardware before installing.
9/16" unthreaded shoulder section provides a clean pivot surface for shackle links and spring eyes -- reduces wear on mating components.
7/16"-20 threaded section accepts a standard nyloc or castle nut for secure retention under road vibration and dynamic suspension loads.
Designed to Lippert component specifications for compatible spring hanger and shackle assemblies used across many towable RV platforms.
Intended for replacing worn, bent, or corroded bolts discovered during suspension inspection, axle service, or spring replacement.
In a standard RV trailer leaf spring suspension, the spring pack is mounted between a fixed front hanger and a rear shackle. The shackle allows the spring to change length as it flexes. Shoulder bolts serve as the pivot fasteners at the hanger and shackle connection points. The unthreaded shoulder -- not the threads -- carries the shear load, so the bolt diameter and shoulder length must match the hanger and shackle bore precisely.
Using an incorrect bolt length or diameter creates slop in the pivot, accelerates wear in the hanger bushing, and can compromise suspension geometry under load. This is why Lippert specifies part 271254 for the assemblies it fits rather than a generic grade-5 bolt.
Shoulder bolts in trailer suspension systems should be inspected at each spring service interval and any time the suspension is disassembled. Replace immediately if you observe any of the following:
The 7/16"-20 threaded end is typically used with a nyloc (prevailing-torque) nut or a castle nut with a cotter pin to prevent backing off under vibration. Do not reuse a nyloc nut that has been removed -- replace it with a new nut during reassembly. Refer to your axle or suspension manufacturer torque specification for final tightening; overtightening can preload the shackle link and restrict proper suspension articulation.
This bolt is designed for Lippert-compatible suspension assemblies that call out part number 271254 (vendor reference 48-4598). It is commonly used in towable RV platforms including travel trailers and fifth wheels equipped with Lippert-sourced axle and suspension components. Lippert is one of the most widely used suspension component suppliers in the North American towable RV market, so this hardware covers a broad range of brands and model years -- but only where the dimensional specifications match.
If your trailer uses a different suspension configuration -- such as a torsion axle, an equalizer-based multi-axle setup, or a suspension with metric or coarse-thread fasteners -- this bolt will not apply. Cross-reference your axle tag or original suspension hardware before purchasing.