I recently put new underlayment under the rear seat. It was made of some sticky tar/asphalt stuff on one side and the other side was made of recycled like grey fabric and thread stuff. I put the sticky tar like side down against the floor and the fabric like side up against the bottom of the seat. The problem is that I want to remove the new underlayment to look at the date code on the floor but the underlayment tar side is so sticky it cannot me removed without destroying the new underlayment. Is this how these underlayment are supposed to be and is this how the factory peices where made? I tar side also had plastic on it which I peeled off, was I supposed to leave this on so it is not so sticky? Maybe this pieces are just not made to ever be removed... Or was the tar side supposed to point up towards the bottom of the seat? I also have flowmaster mufflers relatively close to the floor, is there any chance of this stuff catching on fire?

 

I believe the tar side goes up, insulation 'jute' against the floor, this is the way the factory pieces on my front floorboard are in my '67. With your mufflers close to the pan you've melted the tar to the floor board, doubt it would catch fire but you've made a mess that may get worse as it melts more.
I guess you have a choice of leaving it alone or tearing it up, throwing it away and starting over. There are petroleum based products that will get the tar up (WD-40, etc.) but it will still be a tarry mess to do....your best bet would be to get it really cold to harden the tar and scrape as much up with a flat blade scraper as possible before using tar remover. Don't know how you're going to get the floor pan cold in CA other than packing it with ice.
Jon

 

Thanks I am thinking of tearing it out and replacing it with one from mustangs unlimited. Theirs looks like it is all made of one material and not different materials on each side like the one I have. http://mustangsunlimited.com/itemdy00.asp?T1=PSP104+01 Anyone bought one of the mustangs unlimited ones? How is it made?

 

Mufflers heat the floor and it gets very hot kind of melting the tar stuff, wonder if it is flame retardant?