im gonna take it to a autobody shop
because the drivers side floorboard is rusted and when you bang on it rust falls out on the bottom

is this expensive to do?

 

A floorboard isn't that expensive. The problem is the labor. You have to remove the carpet and crap, set down the new board and trace where to cut the old one, pick up the new board and cut the old, then set in the new and weld it in place. then put back the carpet, seats, etc.

 

I had to do both sides a few monthes back, since they rusted all the way to the rails and the driver's seat was leaning through the floorboard for a while.

I ended up getting a driver-side floorpan (great casting) from Mill supply for $235, and had a welder patch the passenger side. Costed $200, plus the floorpan.

 

It also gives you a good chance to clean everything up. I'd recommend spraying rubberized undercoating in the interior side of the new floor, and then install 2 layers of carpet padding (about $8 from any carpet store). That'll help a lot with vibrations.

Don't bother using the rubberized crap on the outside (rubs right off). Get some decent quality rust-resistant undercoating, or all that work and money will rust out in a few years (or one northern winter).

 

I'm pretty sure I might have to replace mine... we'll see when the carpet gets pulled up. I had a lot of water damage in this car, thanx to a t-top seal this winter. Oh well, gives me an excuse to do the 4th gen interior swap!!

 

I replace mine in my 83 Trans Am during my restoration. Drivers side also, I cut a floor pan out of another 83 Trans Am, took that floor pan to the body shop with the car. I had already Striped the car, and the interior to make the work as easy as possible for the shop to keep the cost down. The total was about $850. It went from the Rocker, to the middle of the trans tunnel and from the weld at beginning of the firewall to the rear seat bracket. It took me a day and about 5 different shops to find one willing to take on the task. they did a great job though

 

Here is the new one