Floor Pan Replacement
In our last article we learned how easy it is to remove the body from the VW bug. With the body out of the way replacing the floor pans is pretty straight forward. But with just a little more effort they can be replaced with the body still in place. The first thing you need to do is remove the seats and floor carpet.
Removing the battery, the rear seat front support, and the heater tubes will give you access to the edges of the pans. If you are replacing the drivers side pan you will need to remove the pedal cluster. You will have to disconnect the clutch cable in the rear to do this. Once everything is out of the way you cut the pan or what is left of it away from the center tunnel and the front and rear chassis supports. We do this from inside or the top of the floor.(If you are doing this with the body off you may want to measure where the old holes were before you cut the pans away)
This can be done with any number of tools
but a sawzall is our favorite.
There is a lip about ½" wide along the edge of both the tunnel and the front and rear supports. We try to stay about ¼" to ½ " away from the lip. When cutting along the chassis supports you will only be able to cut over to the heater channel. The last inch or so on the outside edge will have to be cut from under the car.
Be careful not to cut into the heater channel. Now unbolt the pan from the heater channel (assuming we are doing this with body on) and it should fall out the bottom. Now what is left of the pan along the lip needs to be chiseled away. A muffler cutter with a chisel tip works great but just a hammer and chisel will cut through the small spot welds every inch or so that held the old pan to the chassis.
I have seen this part of the job skipped and the new pans installed right over the leftover scrap. Removing it makes for a much neater job. We go back over the lip with a grinder to make for a nice flat surface to set the new pans on. The new pans usually come with the rear chassis support attached but this is seldom needed and they are never as sturdy as the originals. To remove them just drill out the spot welds that hold them.
If you are doing this body-on then you will have to trim a rectangular piece from each outer corner of the new pan.
This is the small piece that is left under the front and rear chassis support that cannot be removed with the body on. You will be able to measure it aprox from underneath. Try to get it close. A little gap can be filled with seam sealer later. Now a trick for getting the new pan in place. If you bend the front edge of the pan up at a 90 degree about 1" along the edge you will be able to slide it up onto the lip from the bottom.
Then just bend the edge back down. This takes some finagling but works.
Put the body gasket back on the edge of the new pan and bolt it back into place, maybe loosely until you are sure of a good fit. Now you can try out that new MIG welder. You can use either plug welds or a stitch weld along the edge.
A continuous weld is unnecessary and more likely to crack later on. Laying a thick bead of a good seam sealer (urethane possibly) and using sheet metal screws will do the job if welding is out of the question. Once the welding is done go along the top and bottom edges with seam sealer.
Spray the bottom with undercoat and coat the inside with a good rust preventative like POR-15
and you will
be good for years. You can see this done in detail in our Vol.6 Floorpan
repair video available from Bug Me Video.