How to Re-Tap Skid Plate Bolt Holes on a Toyota 4Runner

Many Toyota 4Runner owners encounter issues with factory-installed self-tapping skid plate bolts, which are prone to cross-threading. This guide explains how to re-tap the bolt holes to accept standard M8x1.25 bolts, preventing cross-threading and ensuring a secure fit. Based on personal experience with 3rd and 4th Gen 4Runners, this process is straightforward and beginner-friendly.

Self-tapping bolts, commonly used in 4Runner skid plates, can easily cross-thread, especially if not carefully aligned. Cross-threading damages the threads, making it difficult to secure the skid plate. By re-tapping the holes to accept standard bolts, you ensure a more reliable and durable connection.

I first noticed this issue on my 4th Gen 4Runner when three bolts were cross-threaded from the factory during a lift kit installation that I installed shortly after purchase. After successfully re-tapping the holes, I found the process simple and effective, prompting me to share this guide.

• M8x1.25 Tap: To re-thread the bolt holes.
• Tap Wrench: To turn the tap.
• Cutting Oil: To lubricate the tap and reduce friction.
• M8x1.25x25mm Bolts: Replace all eight factory bolts for consistency (requires a 13mm socket, unlike the 12mm for factory bolts).
• 13mm Socket, Ratchet Wrench and 3" Extension: For installing the new bolts.
• Dremel Tool (Optional): To slightly widen skid plate holes for better alignment, if needed.
• Recommended Tap Set: Craftsman 14-Piece Metric Tap Set #52378.

1. Prepare the Area: Remove the skid plate to access the bolt holes.
2. Inspect the Holes: Check for cross-threaded or damaged threads. The factory holes may already be partially threaded for self-tapping bolts.
3. Apply Cutting Oil: Dab cutting oil on the M8x1.25 tap to reduce friction and prevent damage to the tap or threads.
4. Tap the Holes:
   • Insert the tap into the bolt hole, keeping it straight to avoid misalignment.
   • Turn the tap wrench slowly clockwise. The tap will self-feed into the hole.
   • When you feel resistance, rotate the tap counterclockwise a half-turn to break up metal shavings, then continue turning clockwise.
   • Apply even pressure on both sides of the tap wrench to maintain alignment.
   • Repeat for all eight bolt holes.
5. Modify Skid Plate Holes: If needed widen the holes in the skid plates. In my situation, the front-most skid plate holes (with hooks) were too tight for the new bolts. I used a Dremel tool to slightly widen these holes for easier alignment and to prevent any cross-threading.
6. Install New Bolts: Hand-thread the M8x1.25x25mm bolts into the re-tapped holes to ensure proper alignment, then tighten with a 13mm socket and ratchet.
7. Test the Fit: Reinstall the skid plate, ensuring all bolts secure smoothly without resistance.

• Take Your Time: Rushing the tapping process can lead to misalignment or damaged threads.
• Keep It Straight: Ensure the tap is perpendicular to the hole to create clean, functional threads.
• Clean Up: Remove metal shavings and excess cutting oil from the holes after tapping.
• Check Alignment: Precise skid plate alignment is crucial, especially for the front hook holes.

Re-tapping the skid plate bolt holes on your Toyota 4Runner is a simple and cost-effective fix for cross-threaded bolts. With the right tools and careful execution, you can upgrade to standard bolts for a more reliable setup. This process worked perfectly on my 4th Gen 4Runner, and I hope this guide helps you achieve the same results!

Metric Tap Set