Rust found at right hand (LHD) toe panel

I’ve found a small, I think, rust out at the base of the passenger toe panel of my S3 OTS. A look under the carpet there shows rust damage 2-3 inches aft of the panel. It does not extend to the sill. The frame rail appears solid though you can see some surface rust underneath. I know nothing about body repair or where to start. This is the first hint of rust I’ve seen in 28 years of ownership.

How do I address the problem.


That appears to be surface rust that has formed due to bubbling paint. The bubbling most likely happened because of dripping brake fluid. It destroys paint in a few minutes. You have a couple choices. You can get in there with naval jelly and a Dremel wire brush and power away the rust, crossing your fingers you don’t find penetration. Then prime and paint. Or you could gob thick grease over it and forget about it for now. It will stop the process. No kind of fix, but it will forestall an outbreak of shipwright’s disease.

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No brake fluid on that side but I had a battery above it leaking for some time from an overcharging alternator. Found this when removing the battery and tray for cleaning. I like your idea of arresting grease. At my age that makes a lot of sense.

Remove everything that isn’t adhering to blank metal. Wire brush, rust converter, primer. Even rustoleom is better than nothing.
You can use grease too but you still need to get into all crevices and remove everything loose liberally, and check every now and then.

Rust in the battery area was common.

I went in under the carpet again scraping. It’s confined to an area of the floor within 2 inches of the toe panel, running laterally. Will look to see how much more. The toe panel seems solid on the inside. The area of the Jack mount is solid. Unfortunately inboard of that it rusted through in several places along that laterally as I was able to poke through with a screw driver. The car was heavily undercoated originally by the dealer. Nothing was visible underneath. Water must have been leaking inside over the years. Never driven in wet conditions, maybe a panel leak and many hand car washings. Who knows.

So I guess I’m looking at a repair.

That’s very, unfortunate. This could get spendy. It’s possible to surgically extract just the kick panel assuming the damage is confined to that, but doing so will require yanking off the entire front end. Assuming it’s constructed similar to the S1/2 cars, then it’s spot welded around the periphery, about 25 welds. Each will need to be drilled out, then insert the new panel and weld it in, and then paint. It’s not trivial.

It would be the correct time to strip the whole bulkhead and frames and resolve any other damage and paint everything.

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It is just the very bottom left of the panel looking from the outside that has rust. Is there a reason why the damaged metal can’t be cut away and a patch welded in? Same for the floor. The rusty area doesn’t reach the sill or the jack mount. In fact very recently had it on the floor jack there for an extended time while doing other work near the front end. It is solid.

It would be an excuse to do so but I don’t think Robert is up to that; any serious structural risk by just patching, or regularly oiling the area?

Certainly there is no harm at all in removing everything that isn’t adhering perfectly. Rust is cancer and with any available oxygen it will spread. It has to be covered or removed completely.

I would have somebody look at it and make a patch unless you want to go through the full process. And if he thinks a new panel is the way to go…

Sulfuric acid is said to make tools rust anywhere within the same room if the lid is not sealed on a container?

Sounds like acid damage. If it were a long term seeping brake fluid problem, you’d typically see corrosion all across the bottom front of the panel.

If you go looking for rust, you’ll not stop until you’ve found it and then you’ll flog yourself with the mantra of “bare metal respray” until your wallet is thoroughly empty. The next owner will then simply repeat the cycle.

A more sensible approach is wire brush, phosphoric acid or evaporust the most of it off and then seal the surface. Rust can’t spread without oxygen, moisture and bare metal. Remove any one of those from the equation and you’ll freeze the result where it is at.

I wouldn’t necessarily panic about it being near the engine frames. The engine frame mating captive nuts inside the bulkhead are sitting on a metal plate and not just on that panel alone, so it ought to be double thickness there.

kind regards
Marek

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Merek, would you treat the floor behind it the same way? The soft spots run in a line, I suspect corresponding to the corrugation pattern holding moisture? in the trough.

Everything that the rust has crept under needs to go. Liberally remove coatings where there’s a chance of rust beneath.

I just repaired that area on my Series III last month. Issue existed on each side, but especially driver side. There is a reinforcing plate there that doubles up the metal and creates a nice area for moisture to linger. It rusted from inside out.

I cut off the bottom of the front plate and the last few inches of floor and welded in new pieces, using the front plate that Martin Robey sells after grinding off the spot welds. I spent a lot of time doing it as an amateur body worker, but it came out good. A pro could do it in a fraction of the time.

If you need to replace any of the floor and do your own metal shaping, note that the gauge of metal in the floor is greater than the gauge of the front panel.

Thank you. Sounds exactly like the problem I have. Probably better check the driver side too just to be sure it’s sound.

Please say you did it without removing the engine.

Possibly using an angle drill or Dremel tool you might be able to bore out the spot welds from the inner sides? It’s certainly worth a shot. I would definitely take the weight off the frames either with floor jacks under the engine, or a cherry picker lifting it a bit. You don’t technically need a rotisserie to punch out those kick panels, but that’s if it’s unladen. I doubt it’s possible to fully predict what sort of distortions might occur with 800lbs sitting in the frames. The fact that they have those X pressings is indicative of them being intended as body stiffeners.

Dear Robert,
your car will have had a jute underlay below the carpets and that will have happily soaked up any brake fluid and spread it around all across the inside front of the cabin. Put another way, moisture isn’t a problem for a coated surface, but losing your barrier coating makes corrosives an issue.

A proper drive gets all of this plenty hot and drives off the water, but sitting in a garage where the temperature varies means the amount of moisture condensing/evaporating is continuously changing, so having exposed metalwork (either internal or external) isn’t cool.

What exactly are you suggesting are soft spots? Thin metal? Underseal? Brake fluid soaked paint? This sounds more extensive than the picture you posted.

kind regards
Marek

Mereck, it is more extensive and sounds exactly how Chippewa Rod described his problem 3 posts back. It is not brake fluid as it is on the opposite side of the car from the reservoirs and the clutch line runs outside and clear of the area. It appears, like Dave said to have rotted from the inside. I have no idea how sufficient moisture got in there, maybe from around the A/C hose cover on top of the toe extension. But never driven in rain and that area is covered with a towel under the bonnet when I wash the car.

Anyway, the floor is shot to about 3-4 inches back from the toe panel and about 2/3 its width. The rust on the toe panel does not climb higher than what you saw in the photo.

Rod describes his successful fix to the problem. Erica Moss in the previous post has reservations about fixing with engine in situ. I’d like your opinion on that.

Thank you,
Robert

Battery acid, the rest is from the air…

My car is undergoing a total restoration/rebuild, so I did my repair of those areas on the bare tub minus engine and everything else. plus it was on a rotisserie so I could rotate the tub. Access was not a problem for me. I assume trying to do it on a fully assembled car will be much more difficult, but you will have to make your own assessment of whether it is possible.

Good luck

I did find that the Martin Robey replacement panels very closely matched the contour of the front panels, so I was able to cut the bottom section off those replacement panels, fit them in and lap weld them without replacing the whole panel. Maybe a metalwork expert would have taken a different approach, but that is what I did and I am satisfied with the results.

My car was also heavily undercoated, but the undercoating was damaged at the front edge of the floor by improper jacking of the car by the previous owner back in the early life of the car before I bought it in the early 1980’s, and that contrbuted significantly to the rust problem. Getting that undercoating off is not much fun - I started with wire wheels.

Unfortunately, due to the fact that the flanges on the front panel face forward, it will not be possible to remove the spot welds from inside the car, it needs to be done from the front of the panel.