Fixing Mis-drilled Firewalls

If the worst has happened, and you've drilled out the mounting holes in the firewall in the wrong locations, don't worry. This very common mistake is easy to fix. Drill out the errant holes to a common size, say 1/8 or 1/4 inch. Get a hardwood dowel in the appropriate size, and fit it into the hole very tightly. Soak around the dowell from the back of the firewall with thin CA glue, and cut off the dowell with a razor saw. Sand to the surface of the firewall. The fix is pretty much un-detectable. I also usually paint my firewalls flat black so it looks nice through the cowling.