Lonffery U-Bolts Kit for 2-3/8" Round Axle — 3,500 lb Trailer Fit, 5-1/2" U-Bolts with Plates & Nuts

Durable Lonffery U-bolts kit to secure leaf springs to a 2-3/8" round axle on most 3,500 lb trailers.

This complete mounting kit contains the core hardware needed to attach your trailer's leaf springs to a 2-3/8" diameter axle. The set is sized and specified for the common 3,500 lb axle, with components selected to match a 1-3/4" spring seat width and straightforward bolt dimensions for reliable fitment. Every piece is designed to simplify installation and provide a secure clamp between axle and spring.

Will these U-bolts fit my axle and leaf spring?

Yes — the Lonffery kit is made for round axles with a 2-3/8" outside diameter and leaf springs up to 1-3/4" wide. Check the axle measurement and spring width before ordering to confirm compatibility.

• Axle diameter: 2-3/8" (A dimension)
• Spring seat width: 1-3/4" standard fit
• U-bolt length: 5-1/2" from inside bend to thread end (B dimension)
• Cross-plate width: accommodates 1-3/4" or 2" spring seats

What hardware comes in the Lonffery U-bolts kit?

The package includes every part needed to mount the spring to the axle without sourcing extras. Components are grouped to give you two spring clamps for each side of an axle span.

• Four 5-1/2" long U-bolts
• Two U-bolt plates sized for 1-3/4" or 2" springs
• Eight 1/2-20 hex nuts to secure all bolts
• Dimensions labeled: A=2-3/8", B=5-1/2", C=2" for quick verification

How hard is the installation, and what tools do I need?

Installation is straightforward for anyone familiar with basic trailer maintenance. Remove the old clamps, align the spring on the axle seat, place the U-bolt over the axle and through the plate, then torque the nuts to specification.

• Requires common hand tools: wrench or socket for 1/2-20 nuts
• Work with the trailer supported on jack stands for safety
• Torque nuts evenly to prevent misalignment (follow vehicle or axle spec)

Who is this for: The Lonffery U-bolts kit is ideal for trailer owners, DIY mechanics, and fleet maintainers installing or replacing leaf spring clamps on light-duty trailers rated around 3,500 lb. If your axle measures 2-3/8" and your spring seat is about 1-3/4", this kit provides all the essential fasteners in one box for a quick, secure replacement.