Volkswagen Beetles tend to run forever, so rusted-out floor pans are not uncommon. They are a little complicated to replace, but this type of job can be accomplished by anyone with the right tools and a basic understanding of auto body repair. Replacing a floor pan in a VW Bug is an inexpensive repair that comes with a lot of job-well-done satisfaction.
Remove the seats and floor carpet, then the heater tubes, battery and rear seat support to get to the edges of the floor pans. If you're working on the driver's side floor pan, disconnect the clutch cable and remove the pedal cluster.
Use a Sawzall to cut the floor pan away around the edges, working from inside the car and staying about ¼ inch to ½ inch in from the lip that runs along the edge of the tunnel and supports. When you get to the heater channel, you'll need to cut from under the car, just for the last inch or two. Cut the last of the pan away from under the car, carefully avoiding the heater channel.
Remove the pan bolts from the heater channel, and the floor pan should drop out.
Chisel away any remaining edges of the floor pan with a chisel-tip muffler cutter or a hammer and a chisel, and grind the lip edges smooth.
Prepare the new pan by drilling out the spot welds that hold the rear chassis supports attached to the new floor pan. Use the originals instead; they will be sturdier. Since you're replacing the pan with the body still on, you'll need to use the Sawzall to trim out a rectangular piece from each outer corner of the new pan where the body attaches to the frame.
Bend up about 1 inch along the front edge of the floor pan. This will allow you to slide the pan onto the lip from under the car. Once the pan is in place, bend it back down.
Replace the gasket around the edges of the new floor pan, and bolt it loosely into place. Once the bolts are lined up and you're sure it's a good fit, tighten the bolts.
Weld the edges using either plug or a stitch weld, and then use a seam sealant all the way around.
Spray the pan with undercoat on the bottom and a rust preventive on the inside.
