Getting your steering system assembled properly isn’t just about performance. It’s about your safety and your car’s long-term reliability. Borgeson, an industry leader since 1914, puts precision and safety first in every steering component. Whether you’re building a street rod, restoring a muscle car, or customizing a classic truck, a few extra minutes of careful assembly can prevent major problems down the line.
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This detailed guide shares Borgeson’s best practices for U-joint and steering shaft assembly.
1. Prepare Splined Shafts: Deburring for a Perfect Fit
Before installing a splined steering shaft, inspect and deburr the splines. Burrs, tiny, sharp edges left from manufacturing, can make shafts difficult to fit and may damage components during installation.
Why Deburring Matters: Burrs can prevent a smooth fit between the shaft and the U-joint, leading to binding, damaged splines, and unsafe operation. Carefully deburring ensures the connection is clean and reliable.
Deburring Steps:
- Mark the spline area you’ll be working on with a marker.
- Use a square needle file to lightly skim each edge, don’t remove material, just break off sharp edges.
- Focus on the 3/4” that will engage the joint.
- Clean the area with a cloth or compressed air.
- Test-fit the shaft; it should slide smoothly but securely.
2. Set Screws: Secure and Lock in Place
A properly secured set screw is essential for maintaining a safe steering connection. Borgeson U-joints typically use a 5/16″ Allen-style set screw with a lock nut.
Key Tips:
- Use a mild thread locker (like blue Loctite) on the set screws for maximum security.
- Confirm the shaft is fully seated before tightening.
- Tighten the set screw to 15ft. lbs., then secure the jam nut.
Specific Tip for Double D Shafts: Tighten the set screw on the flat surface first for maximum grip. Only then tighten the screw on the round side. This sequence prevents the connection from loosening over time.
3. Shaft Depth: Avoid Over- or Under-Engagement
Correct shaft depth is critical. Too deep, and the shaft may bind or overload the joint; too shallow, and you risk a weak/unsafe connection.
- Best Practice: Seat the shaft just below flush with the inside of the U-joint saddle, about the thickness of a fingernail.
- Minimum shaft engagement is 3/4″, maximum engagement, 7/8″
- Mark and Prep: Mark the shaft depth, lightly drill (Double D) or file (splined) a small divot at the set screw’s contact point for added grip.
4. Round Shafts: Use Cross-Pinning for Safety
If your build uses round shafts, you must cross-pin with roll pins for secure installation. Round shafts lack splines or flats, so they must be mechanically locked.
How to Cross-Pin:
- Drill one 3/16” hole through the shaft and U-joint, then rotate 90° and drill a second.
- Install roll pins (never bolts) in both holes for full rotational security.
- Never rely on a single pin or friction alone, always cross-pin for maximum safety.
5. Never Weld a U-Joint
Welding a steering shaft into a U-joint is dangerous and should never be done. Welding can introduce hidden cracks, weaken the steel, and removes any chance of future service or adjustment. Always use mechanical fasteners for safety and reliability.
Final Assembly Checklist
- Deburr splined shafts before fitting.
- Apply blue thread locker on short set screws.
- On Double D shafts, tighten the flat first.
- Set shaft depth just below flush; create a divot or groove at the set screw contact.
- For round shafts, always cross-pin with roll pins.
- Never weld steering U-joints.
- Double check all hardware for tightness and security before your first drive.
Your steering system is as safe as the care you put into assembly. Following these best practices ensures reliability, safety, and confident performance on the street or track.
For more technical tips, diagrams, and video instructions, visit borgeson.com. Safe steering starts here.