I recently had the base front carpet floor mats out of my 1985 300D and noticed that quite a few cracks have developed over the years in the black (plastic?) base material (see attached pictures) that sits on top of the metal frame. Applying a small amount of pressure seems to cause more cracking and even breakage.

So, my question:
Does anyone have a recommendation for a product (say, a sealant, gasket maker, etc.) that could be applied into the cracks that would slow or stop additional degrading?

Thank you for any suggestions.

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Someday, you may have to replace a floor panel and you'll be glad to be rid of that stuff. If you really must preserve it, I guess it wouldn't hurt to shoot some undercoat into the cracks.

I wasn't aware that it is so undesirable. I probably inadvertently overlooked previous discussions of it. Whatever the material actually is (which I would be curious to know), it does seem rather inferior the way it is falling apart. Ugh.

Makes sense.

Thanks-

What you're looking at is the cosmetic cover to the asphalt sound insulation. Don't worry about the cracks at all.

When the previous poster said you might be glad to be rid of it, he's right. The stuff is heavy, and hard to get rid of if you need to remove it. If you don't have any rust problems, leave it alone.

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Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

Covering over asphalt sound insulatation - Ahhh.
Sounds like something that those German industrial engineers of that era would select. Interesting. Thank you for clarifying.

Exceedingly little rust on the vehicle and dealt with anytime I encounter it.

Thanks again.

Agree, its just cosmetic.

I like the stuff in a dry car - because it does deaden sound. A pain to mess with for repairs? Yes. Hopefully water can be kept out to avoid those issues...

But if water gets in, all bets are off - this stuff makes it hard to get it out. If anything, the cracks are then of benefit, in that they allow some additional space for diffusion of water, and also some areas that can be vacuumed.

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Yes, it does seem to do a good job of sound deadening.

This is one very good reason to be attentive to any signs of water in the area.

That's another good point.

Thanks for the info.

If the cracks bother you and you'd like to seal them, try this:

https://www.amazon.com/MANUFACTURING-5347-Submarine-Cooler-Coating/dp/B0063KBI7A/ref=pd_sbs_60_3/141-1078669-8773462?_encoding=UTF8&pd_rd_i=B0063KBI7A&pd_rd_r=f2bb7aa6-0c1d-4236-975c-5b46bae9b060&pd_rd_w=Urbrc&pd_rd_wg=sgbf2&pf_rd_p=bdc67ba8-ab69-42ee-b8d8-8f5336b36a83&pf_rd_r=QQ1QM3Q0JX2GGWFBNEZ4&psc=1&refRID=QQ1QM3Q0JX2GGWFBNEZ4

Plan on allowing a week or so to allow the smell, not over-powering but noticeable, to dissipate. Brushes on easily and if applied in thin coats fills the cracks nicely.

Henry's makes a roofing emulsion which works also. It takes MUCH longer to cure and the odor persists for a good while.

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Wow. I thought I was one brilliant cat who knew everything but apparently not... I'd never heard of this. Interesting stuff..." thick asphaltic base" etc.

I sincerely appreciate your letting me know about this. Thank you.