3102-391 – Flange Yokes – 1310 Series – Bolt Circle Dia 3.386″ – Pilot Dia 3.937, OD

Flange Yoke 3102-391 -- 1310 Series, 3.386" Bolt Circle

Sourced directly from the drivetrain component specialists at Universal Driveshafts, the 3102-391 is a 1310 series flange yoke machined to consistent, measurable tolerances. It is purpose-built for applications where the driveshaft must bolt directly to a companion differential or transfer case flange rather than slip over a spline. The 3.937" pilot feature ensures immediate concentricity the moment the yoke is seated.

Technical Data

How the Bolt Circle Drives Compatibility

The 3.386" bolt circle is the defining compatibility dimension -- it must match the companion flange exactly. Attempting to use a yoke with a different bolt circle leads to misaligned holes, requiring elongation that destroys the precision fit. The 3102-391 is stocked specifically for flanges with a 3.386" PCD, so there is no guesswork at the bench. It ships with 6 bolt holes of 0.415" diameter, ready for standard or metric hardware depending on your vehicle platform.

Pre-Installation Checklist

• Measure companion flange bolt circle -- must equal 3.386"
• Confirm pilot diameter of mating flange matches 3.937" pilot
• Check that your u-joint series is 1310 -- cap size compatibility is non-negotiable
• Verify CJ-to-flat (2.592") against cap depth in your u-joint to prevent interference
• Clean and de-burr both mating faces before final assembly

Build Quality

Every 3102-391 is forged from carbon steel for grain-flow strength, then machined to finished dimensions. The ear bores are sized for 1310 series cap diameter -- no reaming required. Whether this is a stock replacement or part of a custom high-performance build, the part will handle the torque loads the 1310 series was rated for without deflection or fretting at the bolt faces.