floorboards

There is some black plasticky cover on the floorboards inside the car. It is starting to crack and come apart. What is the purpose of this cover(sound deadening,rust protection)? It's an '86 carrera. Was this rubber when new and just turned hard over the years? What can I use to replace this(Dynamat maybe)? I'm worried water will get trapped under and start to do it's magic. Any Ideas?

I assume you mean the black stuff covering the whole floor pan. I assume so, and it is a bitumen based sound deadening - ie like Dynamat.

You can remove it pretty easily using a heat gun and a scraper. When it is out, check for rust as it can trap any water that comes down in. Given you have a well-galvanised Carrera this shouldn't be a problem, but it doesn't hurt to check.

Replacing it is a piece of cake. Basically clean up the residue as best you can, then peel and stick the new sheets, using a heat gun (or even a hair dryer) to help them conform to the shapes of the floor pan. Make sure to eliminate air bubbles.

In terms of what to use, Dynamat is an option, but expensive. I used a more generic product made by Bostik but probably not available in the US (and about half the price). Someone else can probably give you a recommendation.

I would recommend replacing the fibre underlay stuff too - it is very very cheap at your local upholstery shop.

I did a quick search on "sound deadening" and it came up with this link, which is probably as good as any:

http://www.projecttransam.com/projects10.htm



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Cameron Baudinet
1975 911S

Sound deadening stuff...replaced what was in the 914 I have along with the rear sound deadening in the interior of a 74 911. I would recommend you go to an store that sells automotive paint. That is where I got my stuff. The one thing you will find is that the stuff can get really heavy and really costly. To do the rear deck and the area where the seats used to be in the 911 it cost around $85 for the material.

Paul