Death foam discovery ‘73 wagon

[Pepperbilly]

Apparently on the rear most fender upper bolt mount, foam was injected between these inner panels. Looks like it can hold water and cause cancer. Found this only on the passenger side. It is an easy repair but could have been much worse. I believe the problem is promoted by old fender seals that seep water. I also would like to understand why the foam is needed at all? The driver side has no problems so that limits damage repair.
Bill

[raygreenwood]

Yes...its all up and down teh C-pillar sections of all three models.

Grind/carve out as much as you can. It was a sound deadener.

I was looking up what might dissolve that stuff quite a while back. Google "what dissolves isocyanate foam". Start reading.

https://www.coatingspromag.com/industry-news/2015/...-equipment

Most can be flaked out and sanded away if you can reach it. The problem is that when teh body work leaks it fills with water and stays there to rust.

Ray

[Pepperbilly]

Ray,

I also have a ‘75 Super with the same foam. On a beetle I understand sound deadening idea because it cuts off the sound from the engine compartment... there is a direct path for the sound. But on the wagon? The engine compartment/channels are made differently, I think.

Bill

[Hawker]

Gents,

VW were not the only German car company experimenting with this blown isocyanate foam and in every case it caused corrosion. Condensation is trapped by the foam against the metalwork and it simply corrodes its way out. The “Jeans” Beetle and “GT” models would rust in places that no previous beetle had ever rusted in! VW stopped using the foam in the mid 70’s so the “Last Edition” Beetle models were immune and have lasted longer.

My method is to flood the box sections containing the foam with old engine oil, from above and let it soak into the foam. The problem with trying to removing the foam is that it’s often in box sections that you simply cannot get into.

BR,

Rob

[heimlich]

They really put that stuff everywhere. It's important to remove the rust and rust bubbles. You can't just treat it with a chemical as it may pop up years later after you paint it.
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[raygreenwood]

[raygreenwood]

Note....the other thing this foam is used for is to stop panels from rattling.....especially from wind and body flexing at high speeds.

You can see this usage where splotches of foam are used between the ribbing of the front hood and the outer skin on the trunk and is also probably the main reason it was used between the hin valance and spare tire well.

Ray

[Lars S]

These images are out of the factory workshop manual and are supposed to show where the foam was injected at factory. Note that on the coupe half of the large D-pillar is filled.

This is a repair instruction for the sills...

...and here are two examples of heavy rusted coupe pillars, i bet condensed water has been laying on top of the foam-plug inside the pillars..

Lars S
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[Pepperbilly]

Lars S,

Always amazes me that people like you have information like this around!
Hopefully my wagon does not have too much of this foam... I see no other problems other than what I have shown. This stuff is nasty and I don’t want to cut into my beautiful wagon any more than I have to. I also have a ‘75 Super with this foam but no problems at all. I think it comes down to what climate the cars lived in and if they were garaged or not.

Thanks for your documents,
Bill