EEK! Look what I found under the Carpet!

[86 911]

My rear carpets were soaking wet so I decided to take all the layers of carpet off. What I found were about 10 drilled holes about 1/4'' in diameter that were left uncovered and some surface rust in one corner. Also, the coating on the floorboards is cracking and dried out. Is this serious? I'm just going to put in bolts in the holes and tar them over and then sandblast the rust. If this were your car, what would you do? Is the metal still good/strong?
Here are some photos:


The Rust:
The rest of the floorboard:

[86 911]

OK, I got a screwdriver and started scraping at the "rusty part. It actually is just a coat of some brown residue on the floorboard coating, so I don't think that is rust. I only have the holes to deal with now. Should I re-cover the floorboards with coating?

[Svensson911T]

I would por15 your floors

[RIX 911RS]

I would take a wire brush to the rust or sandblast it just like you said, then paint the whole floor with POR-15 and cover up the drilled holes with seam sealer or fiberglass.

[86 911]

RIX 911RS, that looks super! Looks brand new to me. Well, I started in with a putty kinfe and got about 80% of the driver's floorboard scraped of the old coating so far. The coating is just coming off in brittle pieces mostly. I found some light surface rust on the actual metal and some more serious rust under the seat railings.
So does this procedure sound good?:
1) Scrape whole floorboard clean
2) Fill in holes
3) POR-15 the floor.

BTW, where can I find POR-15? Would Pep Boys or AutoZone have it?

[LoveMy911]

http://www.por15.com/
www.prp-porstore.com

[David E. Clark]

I agree with the others about POR 15. I used it to coat the trunk bed and frame of my 1971 SAAB Sonett. Terrific stuff. Very durable! Check out the POR-15 Test Results page.

[s5uewf]

Sonett, a fun little car - I had a 1969 model. Weird combination of parts, but fun.

[SLO-BOB]

I'll agree with the otheres-POR. I did it to one of my BMW 2002s and it worked VERY well. Order it right from POR and be sure to follow all the directions to a "T". It's critical. If you buy the kit that has the cleaner, primer, and coating you'll be happy. The silver is a little heavier fyi.

The questions are-where is that water coming from? Why are there holes drilled in the floor? Sounds like you need to solve that issue before saying "mission accomplished".

[ChrisBennet]

Maybe you should leave the holes for drainage.
-Chris

[86 911]

My dad went to OSH hardware and picked up some rustoleum since the sales guy there said it was some of the best stuff to get rid of the old rust and keep rust from coming back. Will Zinc and then Rustoleum coating work just as well as a POR product?

[SLO-BOB]

No.

[real550A]

where is that water coming from?

Standard equipment on a cab or targa, I'm afraid.

[DaveE]

No seconded.

[86 911]

Why are you saying no to Rustoleum? What's the difference?

[cashflyer]

Never tried the POR-15, but on a previous project car I had the entire cabin floor sandblasted and then Rhino-Lined. Let's see that b**** rust now!

[porschenut]

Maybe I missed something, but I don't understand why you're thinking of doing anything to the floor. You have already determined that there is NO RUST there, so the only problem is the holes. They're small enough that you can easily caulk them and be done with it.

The cracks in the old paint are nothing to worry about. My 86 has them and so does every other Carrera I've ever seen. None of them have any rust. I think you're about to do lots of unnecessary work.

[86 911]

I finished scraping the old coating off and I found a lot more surface rust than I thought I would find. Most of it is under the seat rails and in the corners. I'm thinking it's best to exterminate the rust now instead of it getting worse. What's wrong with using rustoleum though?

[Por_sha911]

86: I think the prevailing thought is why do the job half way and then find a bigger problem later? Most folks don't pull up their whole inside to check for rust on a regular basis. Rust is merciless and the arch-nemisis to any auto. Unless this is a fix-it-and-flip-it job, go ahead and use the POR-15 and you'll sleep better at night knowing it will never have to be done again.

[86 911]

I went ahead and pulled up some more carpet and the rear seat cusions, and WOW! You guys should have seen how rotten the cusion was and the moisture was in the cusion. I also went ahead and filled in the holes tightly with heavy duty metal screws. Tomorrow I'll JB Weld over the screws and over the next couple of days, clean the floorboard/seat cusion mounts well to suit the POR and zinc primer.

Today's progress:

The rotted cusion: