I recently removed the front seats and carpet from my 1983 300sd to track down a water leak that turned out to be from a rotten AC condenser drain hose. I took up the sound deadening material from the driver's footwell, and a good bit of the rubber coating from the rear footwell to assess and remove any rust. Thus far, all the corrosion has been superficial, but on the serious side of superficial.

The rusty trail leads to the corner where the rear floor meets the bit of steel on which the rear seats rest. I can see evidence of water having passed through under the seat.

What is the best way to get a look at this area? Removing the rear seat or perhaps cutting a little access hole just above this area? I'd coat the raw edges of such a hole with miracle paint.

I have to ask what the best way is to get to the rust inside the brace that would be below the driver's seat? I wish I knew a trick that would let me get in there to remove any loose rust and take back a bit of the paint surrounding the rust in order to apply miracle paint.

Any advice will be gratefully received.

The easy way. Use this marine grade cosmoline to coat the surface. It's tough and easy to apply.

https://www.amazon.com/CRC-06026-Heavy-Corrosion-Inhibitor/dp/B07N1VLTFD

Or

Obtain QUALITY stiff dull puty knife.
https://www.amazon.com/Hyde-Tools-01140-2-Inch-Stainless/dp/B001VEA860

Remove all LOOSE PAINT, debri, and rust, with moderate force scrape from the inside (rust epicenter) out (edges of paint) until you run into tightly adhered paint. Never paint over loose paint.

Clean surface with solvent until It's completely contaminat/dirt free, wipe surface with distilled water to get a normal ph on the metal. Dry the surface with lint free cloth.

Get a wire wheel with a right angle grinder, wear a respirator, safety GOOGLES, a face shield and hearing protection! Bust the rust till it's bare metal. Break out a 80 or 120 grit sanding disk, roughness the surface thoroughly to develop a surface profile.

Feather the edge with 240 grit sanding disk. If you're inexperienced, I suggest feathering by hand with 120. You want a smooth gradual transition from paint to primer to bare metal. The feathered area can be a few millimeters wide or around 1/4" roughly.

Photo #4 is a perfect example of a feathered edge.
1968 Mustang Fastback Resurrection: Underside Floor Finish and Door Striker Plates

Clean metal surface with a solvent until no more contaminants remain.

you'll end up using some sort of marine grade two part epoxy primer and paint if you want a durable coating. Use a respirator for fumes!

Lastly you'll need to find the required dry film thickness of both the primer and paint, a wet film thickness gauge will be required. Along with knowledge of percentage of solids by volume of the primer and paint. If a primer requires 4 to 6 mils dry, if the paint is 20% solvent. You need 5 to 7 mils wet. Also watch out for high humidity, if it's too high you can't paint.

Keep in mind, all epoxies have a pot life dependent on temperature, pot life is how long the paint is good after the two parts are mixed, it isn't long at all so DON'T mix the whole thing at once. Portion it out exactly as the manufacturer says.

SOME epoxies have an induction time, induction time is how long you must wait until the paint or primer is ready to use.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Does anyone know about sacrificial anodes use for cars? Or the electrical protection systems they sell? How effective are they if at all. On cars.

I am not computer literate enough to post pictures. Yet pictures of actual rust do help. Geographical location determines to what extent rust develops.

In the salt belt where we live we actually look at it as having three stages. Although it is just the same oxidation of metal attempting to return it to its natural state again. Most miracle paint type products are moisture cured urethanes.

Sounds like superficial surface rust in your case. Probe with a screwdriver or awl if uncertain. In the 1960s and 1970s Mercedes had horrific corrosion issues. In some regions of north America. Mercedes knew it and still persisted with the same methology on their unibodies. Worse than no protection of their metal at all in our region.

Theoretically the better bond the urathanes or epoxies have the less chance of oxygen getting in and also perhaps less space for condensation. Dealing with rust on these cars is harder than most I tend to believe on average.

Oddly enough although I have not tried it. I have several electric paint removers that may heat that sound dampening material enough to soften it to remove. Not heat guns. You do not want to make a mess of the interior when getting prepped for whatever you decide to do.

Zinc anodes will only help with galvanic corrosion, at also the anode has to be submerged in saltwater to work. Basically no.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Do you no how to get the Pictures from your Camera or Camera memory stick into your Computer?

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84 300D, 82 Volvo 244Gl Diesel

Never bothered to investigate it. I know it is fairly simple though.

Thanks for the replies. I know how I'm going to treat the rust once I get to it, it's just that I'm not sure how to get to it, particularly the rust under the rear seat that I'm sure is there... I need to see what's on the other side of the blue circle in the attached image. Would removing the rear seat give me access to this area? The other option being cutting an access hole just above... Unless anybody has other suggestions.

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This is the other area I can't figure out how to get into to prep it for miracle paint. These structures run perpendicular to the length of the car and are located under each of the front seats.

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I can't see how making a small hole to insert a camera would cuse any problems. That is how after market shops wax the inside to prevent rust. On the w210 cars on the front of each channel is a plastic knock out allowing access. Those are structrural just as a note.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

Thanks.

(This is not on an apple computer)On my old computer I only have USB ports. You either hook the camera up directly to that or you connect that to a card reader and stick the camera memory card into it and you will see something similar to the attached picture. (Newer Computer often have a Camera Memory Card Reader built in with the Computer.)

Pick which one you want to see if you can find your pictures. You can open my pictures or pictures (in documents) and drag the there.

That would get them into the computer.

If you need to alter the size of the picture or you want to add text or arrows and so on you can go to Paint. Open Paint and from there open your file and it will display in paint.

One of the reasons you need to go to Paint is because the picture can only be of a certain max size or you won't be able to attach it to your post.

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84 300D, 82 Volvo 244Gl Diesel

Classic car owners deal with this concern, especially corrosion on the inside of frame rails. In those days, manufacturers didn't dunk the final bodies in primer as most do today, so I think the inner surfaces are unpainted. Eastman offers kits to spray rust converter thru the access holes to the inside of frame rails. I think you need to clean those areas first. I did this in my 1965 Dart when I ripped the passenger floor out, but I ran a rag soaked in Rust Destroyer thru the front frame rail after cleaning (open U-channel at top w/ floor off). Better than nothing.

I agree that cosmoline should work. Rust isn't really a cancer, it just spreads because it is hard to seal oxygen out because rust is porous. If nothing else, perhaps spray Rustoleum "Rust Inhibitor" (shovel on spray can). I think it is a cosmoline-type wax. I use it on nuts & bolts that I can't paint.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans