How to Repair a Hole in a Mufflerby Russell Wood
A muffler is one of the secret saviors of your vehicle. Without it, the exhaust system is obnoxiously loud; if you've got a hole in one, you know it. Repairing that hole in your muffler involves taking the vehicle to a muffler shop, or crawling underneath the vehicle with a welder and some steel and patching it yourself. If you have a MIG welder, you can do this on your own time, and save some money.
Lift up the rear of your vehicle using the jack, and place the vehicle on jack stands. Make sure everything is secure before you crawl underneath the vehicle.
Locate the hole in the muffler. It should be fairly easy to spot, as loud mufflers generally won't have small holes. Measure the hole using the tape measure, and transfer those measurements to the 18-gauge steel using the permanent marker.
Cut out the steel to the patch size, using the tin snips.
Clean the area around the hole in the muffler with the wire brush. This will ensure you get a clean weld.
Put on the welding helmet and gloves, then turn on the welder. Hold the patch over the hole and place tack welds in the corners of the patch. A tack weld is a short, quick weld that is designed not to produce too much heat while still connecting the two pieces.
Work your way around the perimeter of the patch, continuing to tack weld, so you do not build up too much heat. The goal is to tack weld the patch all the way around so the welds appear to be one continuous weld.