Steel thickness and material properties of the W116 chassis

Started by olives17, 19 January 2023, 09:38 AM


Good day :)

I thought I'd post this here as I'm probably not the only one who has wondered about this.
As I am restoring my own W116 ('74 350SE) I wondered about the quality and thickness of the steel as I would see how close (or off) the properties of what I bought was compared to original. This lead me to shoot the Classic Center an E-mail on this. here is what they said:

"thank you for your e-mail. The body parts of the W116 series were usually made of RR St14O3 or RR St14O5. Depending on the mounting location, different sheet thicknesses from 0.88 mm to 1.25 mm were used. To determine which sheet thickness was actually used you have to measure the parts in your vehicle."

To save you some time, I googled the Material properties.
ST14-03 (now called DC04): Yield = 210MPA (30.45KSi), Tensile Strength = 270-350MPA (39.2-50.8KSi)
ST14-05                    Yield = 220MPA (31.9KSi), Tensile Strength = 270-350MPA (39.2-50.8KSi)

Whatever you decide to use, its probably better than the absence of steel (aka. a rust hole) so I wouldnt loose sleep over not picking steel with the exact properties.



Interesting. Doesn't seem much does it? I know when I replaced the front wings I thought them a bit thin in comparison and thought them just replacements. I know there is all the paint and under coatings which does make it seem much thicker but those dimensions don't seem credible. I always overcompensate and I suppose the engineers know what they are doing but doesn't give you much confidence. Perhaps we are relying on the paint and coatings.
1974 450SE silver green/bamboo velour/green vinyl roof


I just use 20ga steel.  It's not a spaceship. I think most MB formed parts are @ 22ga. I like the thicker steel for ease of welding.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'21 E450 Cabrio