hello nick,
not uncommon.

i've repaired similar rust spots.

here's a site to guide you--dave shannon's pages.
http://volvo2.homestead.com/Rust.html

i used por-15 instructions and products to repair the floor pan and other areas of ruston mine and my brother's cars.

for the last thing, i used 3m rubberized undercoating spray for sealing the bottom after repair.

you will need a drill, wire brush attachments, por 15 (or other similar products).

i suggest taking out the seats, taking up the carpet for a full review of the floor pans.

now, my floor pans are just as good as the day my wife bought the 86 245 (~4-5 years ago when repaired).

write back if you need more advice.

regards,
byron golden
86 245
92 245
94 949
92 244 parts car

Had a similar experience with my 1983 245GL when I first got it. PO complained of a hole in the floor under the driver's seat.

When I stuck my hand up under there was a football-sized hole. The heavy gauge piece that is the seat mount was untouched. Ultimately I had a jake-leg body guy weld in a piece and the hole was gone forever.

The cause? The PO had gone to her dealer for everything and they had "done" the a/c system. The air plenum, two halves rather than the single piece in my previous 240's, had not been sealed tightly and condensation had leaked into the carpet for years.

When I pulled the carpets, which were dry to touch, the sponge-rubber padding was gooey wet in all four foot-wells. And there was a high-water-mark around all fot well, in rust. The water stayed in the pads because of the rubber water-proof scrim on the top surface of the pad.

So - check the windshield for leaks, and consider that in one of its previous lives the car got water that stayed for a long time without being obvious to touch or smell.

Good luck, and feel thankful that your leak doesn't smell like anti-freeze.

Bob

:>)

Had a similar experience with my 1983 245GL when I first got it. PO complained of a hole in the floor under the driver's seat.

When I stuck my hand up under there was a football-sized hole. The heavy gauge piece that is the seat mount was untouched. Ultimately I had a jake-leg body guy weld in a piece and the hole was gone forever.

The cause? The PO had gone to her dealer for everything and they had "done" the a/c system. The air plenum, two halves rather than the single piece in my previous 240's, had not been sealed tightly and condensation had leaked into the carpet for years.

When I pulled the carpets, which were dry to touch, the sponge-rubber padding was gooey wet in all four foot-wells. And there was a high-water-mark around all fot well, in rust. The water stayed in the pads because of the rubber water-proof scrim on the top surface of the pad.

So - check the windshield for leaks, and consider that in one of its previous lives the car got water that stayed for a long time without being obvious to touch or smell.

Good luck, and feel thankful that your leak doesn't smell like anti-freeze.

Bob

:>)

Windshield leaks, resulting in wet carpets was the cause of my rusted floorboards. Have someone run a hose on the windshield on drivers side and look in the fusebox with flashlight at the same time. see ant water? I did. Are your carpets wet?