Hi all,

I have a 1984 300sd with some relatively small cracks in the dash. They are on both sides, starting from the corner of the speaker, about 2" in length. Is there anything I can do to stop them from spreading? Can I drill a small hole at the end to decrease the stress concentration, like one would do in steel?

Also, the wood veneer is curling off of the trim in multiple places (most notably, the glovebox and doorhandle surrounds.) It is delaminating from the interior. How can I fix this? I tried removing one of the door handle surrounds, and reattaching the veneer to the aluminum using contact cement and clamps, but it was too curled up and the edges peeled off.

Thanks,
Jack

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Jack
1984 300SD. 115k miles.

Four years ago I drilled the ends of the cracks on the dash of my TD with a bit just slightly larger than the crack. They haven't spread since.

I did it while I had the windshield out for replacement which made it MUCH easier.

No idea how to keep the veneer from curling/peeling once it starts.

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Chad
2013 Jeep Unlimited Rubicon
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL

I don't think you can stop the aging process. Mine was doing all of the above and then one morning I came out and there was a six inch crack down the middle of the dashboard. Search E-Bay for NOS dashboards or find a good used one - preferably from a later W126 because it was a harder plastic. Send the wood out for refinishing or refinish it yourself. Any other method will just cause you endless frustration. I found that once I did the above work and fixed B-pillars, seats, vanity mirrors, plastic trim around seats, etc. that my enjoyment of the car has gone way up.

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1984 300 SD 384,000 Miles

Mine started 4 years ago, and I replaced the dash last week. They were about 4 inches in length and I couldn't stand it any further.

I've used Meguiars Ultimate Protectant since it has UV protection in it and I think that helped keep the cracking at bay for as long as possible.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

what I do is wipe/rub my interior down with Lexol leather conditioner first, then I use Black Magic Pro Shine Protectant. That stuff is amazing. Keeps the interior looking shiny and new for weeks. My interior looks immaculate with no cracks on the dash or the seats...arm rest is a little worn, but that's it. I say give the 2 a try if not the go for the Black Magic.

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1990 190E 3.0L

One big reason for the cracking is varying rates of expansion; as the top layer hardens, it no longer expands and contracts at the same rate as the bottom layers, which in some cars can be a steel or aluminum substrate or stamped framework. This is especially evident at openings and corners, where the need for flexibility to accomodate expansion is greater. (the expansion is "photographic" where everything gets bigger, including the inner edge of an opening, not just the outer edge of the dash)

Aside from applying your solution of choice to keep the dash pliable, minimizing the expansion and contraction will also help a lot: use an opaque sunshade as much as possible, even for indirect sunlight.

The car's glass absorbs short wavelength UV (UVB), which helps a lot, but passes the long wavelength UV (UVA), and of course, much of the visible light, which greatly heats up the dash and raises temps, leading to cracks. I'd almost say that heat (and the expansion and dryness it causes) are more of a dash-killer than UV itself, but what do I know? I haven't even stayed at a Holiday Inn yet.

Good luck, and stay flexible.

I use a folding windshield sun shade all the time since I acquired the car a year ago. Even on cloudy days.

Not only does it help protect the dash but the car stays much cooler as well.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

How can I get the dash wood that has come off to flatten out?

I have a number of collector cars with original "uncracked" dashes,,,,including my 1967 corvette,,,,,,,so I have spent many a day worrying about this stuff.

What I use is a protectant called 303 aerospace.
303 Protectants and Cleaners is the premium choice for car enthusiasts, avid boaters and home owners since 1980

It seems to keep the vinyl pliable and I also keep my dashes out of direct sunlight with towels while driving, and sunshades when parked.

I'm not usually big on spray on products, but this stuff is worth looking into.

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Alain
independant MBZ tech since 1981
http://www.motorsportlegendsks.com/

My 87 300D was cracking in a couple of places. I took black silicone and worked it into the cracks. Wiped off the excess. Looks better than having all the cracks

Mercedes dashes from the mid to late 80's are notorious for developing surface cracks due to design and materials chosen. In the 90's better cover material was used and cracking was dramatically reduced. Using a UV blocker, like Aerospace 303, prevents excess outgasing of the petrochemicals in the vinyl skin and avoiding temperature swings reduces the expansion/contraction of the aluminum dash shell.