Roof Repair

trsfa

Member
About a year ago, I had to have the front panel of my roof replaced. Later the roof was repainted by the local Sprinter dealer, under warrany due to rusting. They damaged the seam, causing rain to pour into the interior of the van. Also, it seems that the less pliable sealer will not tolerate the flex of the large bodied van. Be advised that if you have this repair done, inform the body shop of the unusual movement of the large unibody, in that most domestic body shops are used to repairing American made vans.
 

dronsin

Member
I believe the sensitivity of the frame and body in torsion is a major issue with DC, and pointed out in their body builders data. Typical truck frames are channels, which do not have much torsional stiffness, so bodies that are mounted are often done so with loose or spring held high deflection mounts....look at a concrete transit mix truck.

The sprinter frame members are closed rectangle sections, so stiff, but not really much contribution in comparison to the body itself. There are 'closed' or tubular portions at the body bottom, or skirt, that probably add more. Cutting an opening, say on the roof, or modifying a member that carries twist can cause lots of other points of flexing stress, often with concentration factors that make ugly problems.

MB offers dual sliding doors, which pretty much eliminates the body envelope itself as stiff, unless doors are shut and wedged, so my guess is that the lower body skirt sections are the most sensitive to avoid compromizing. Note that the cab chassis comes with a second 'frame' on top of the original to give a minimum frame competency, probably with little regard to any stiffness added by built on bodies.

Some american vans, and pickups with open box beds (again no torsion) have had problems with torsional oscillation and vibration (NVH in parlance). You can often see and feel this riding in the back.

Doors help close the back section and will take loading when the body twists and deforms...maybe another place to watch for wear and adjustment.

Dale Ronsin
dronsin@earthlink.net
 

Zach Woods

New member
This also likely explains why Daimler Chrysler is so cautious about allowing others to cut openings in the roof.

It is my understanding that, to date, only Westfalia has been factory authorized to cut open the roof and add extra high roofs.

I had also noticed the unusually large "rocker panels" that seem to ring the outer edge of the bottom of the vans.

Probably worth noting that deformation of these "rocker panels" (in an accident, for example) could seriously undermine the structural rigidity of the "stressed box" of the vehicle.

Zach Woods
 

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