trunk restoration= this month- Black tar

[stratmanedh]

I am having my whole trunk floor  in my 70 280 SL redone due to rust and I am not sure what material is the back/ waxy material that is in some, of the grooves or " wells" in the trunk sheet metal. I am attaching a photo from motoring investments and I typed the letter "A" in the areas where the material is.I did call the dealer where I buy all my parts & they sent me part #0000-983-29-91- Called "grey paste" for $10.80 a meter..but that stuff seems more like a sticky tar paper..almost like an underlayment. Can anyone help with this?
I am also, curious what the proper underlayment/sound/heat barrier is for the floor pans as that area will be next. Is the grey paste perhaps meant for that area??
Many thanks!

[Jordan]

One of the cars at PUB 2011 this year had an unblemished original trunk floor.  It was in pristine condition and Tom was very excited to see it.  Those areas you have marked are in fact the same material as the firewall.  Most have lost the perforations/indentations you see in the firewall because stuff is continually put on top of them over the years so they become flat looking.  I don't know about the floor pans.

[seattle_Jerry]

I'm skeptical that the long strips are the same as the firewall. I had a 1970 220D for 30 years from new. Unless they changed how they did the trunks (and the trunk was very similar), it had a tar like impregnated material of somesort. Never did it have the waffle pattern as is found on the firewall. Also the firewalls seem to flake apart while the tar substance just got fissures. Their purposes were completely different as well. One was to reduce heat/engine noise to the cockpit, the other to reduce vibration/sound coming from the large trunk panel...but I could be wrong.

[Peter h]

here some pic, i also think its not the same as the firewall

Peter

[49er]

I agree that the material is definitely not the same material as the firewall, under dash and foot well padding. Much thiner. Here are a few picture that also show the "tar" like substance. After looking at these pictures it looks like I need to get out the vacuum/hoover and do a little "detail work" in my trunk/boot:-)

John

[stratmanedh]

thank you guys for your replies. After further research Dave Gallon sent me the following: (when the part arrived it does look like a thick tar paper apparently when applied with a heat gun it changes its appearance. It evem smells like tar hence " bitumen"


The January, 1972 (edition C) 250/280SL parts catalog
shows the part you are asking about. The description
is:

"Insulation (order by the meter)
bitumen felt cardboard, 3mm thick
luggage compartment, lateral, 85x570mm, quantity 2
luggage compartment, central, 192x595mm, quantity 1"

The dimensions do not seem to quite fit but, nevertheless,
I am certain this is the part in question. The part number
is "000 983 30 91 replaced by 000 983 29 91". Now, you
will note that 000 983 29 91 is the part your dealer provided.
I know this part and it is certainly not what you want (I have
it in stock). To my surprise, it appears the original part number
is available and not dramatically expensive:

[stratmanedh]

Trunk floor panlels: are they welded to the rear quarter panels i've gptten different replies from many people. Does anyone have a true diagram or build sheet for the  proper trunk installation? I have heard they werent welded but sealed with Butyl tape originally..i have also hear they were welded?

[66andBlue]

Hey guys, you all can have it both ways!  
As Jordan mentioned there was an original 250SL delivered in Europe at this year's PUB that had the diamond-pattern strips in the trunk. And this car is not the only one. Attached are photos from a car made in April 1965 that has them in the trunk and of course on the firewall. (As an aside, it also has jute and not foam backing on the firewall piece - another somewhat rare combination.)
My 230SL made in July 1966 does not have the pattern but the smooth surface that is shown in several photos here.

What I find surprising in John 49er's photos is that the smaller strip has almost completed "melted" to the metal whereas the wider one next to it is well preserved. Different materials, or is the wider one better protected from the heat generated below by the exhaust?
His photos also show that the material used to hold down the cables is different from the the others.  Tom Colitt mentioned that in the same car he has seen mixtures of different materials also - I hope he chimes in here.

[66andBlue]

... I have heard they werent welded but sealed with Butyl tape originally..i have also hear they were welded?

While visiting the paint shop today to check up on my 280SL I noticed another 280SL with a badly rusted trunk.
I asked the chassis man how the panels were installed originally and his answer was that he believes that most of them were welded and sealed but he had seen some that were welded all around. He explained that he welds in the new panel on three sides and if the quarter panel is undamaged and straight and the contour of the outside lip of replacement floor panel fits perfectly then he seals it to the quarter panel. Rational being that in this way one can remove a quarter panel without having to cut it away from the floor panel. But when the fit is not good and the customer also does not want an new quarter panel then he welds it on - but he does not like to do it that way.