2003 Cayman Structure cracks

[InspectorLance]

I have this 2003 Monaco Cayman 30pbd. 46k miles. I just purchased a few months ago. I have found lots of cracks in the 1.5" steel tubing that is between the frame and floor. This is the R4R chassis. It would appear that the frame has been flexed too much and caused damage to the tubing and welds. Some cracks are at welds and some mid tube. I figure that this could be caused from twisting the coach with the leveling jacks or maneuvering on very unlevel surface. The seller did have a steep uneven driveway and would do a multi point turn to turn around. The cracks are mostly near the front, a few are mid chassis. None near the rear. Two areas have previously been welded where the frame meets 1.5" tubing in the very front.

I have a few questions.

Is there a repair shop in Washington or Oregon that would be experienced in this type of repair. 

What is the cause of this type of damage? Is it possibly a main frame issue? There are no cracks in the frame and bolted in cross brackets look good.

The middle bottom of the windshield does move around when you hit a bump. You will see a pict where the vinyl dash is a little torn up from this movement.

My brother is a great welder and fabricator. I was thinking of just having him weld the damaged areas, but I want to make sure to deal with the root cause first. 

What are your thoughts?

The PDF file has more pictures with circles and arrows. 

Thank you.

 

 

combo picts.pdf

Edited September 9 by InspectorLance

[InspectorLance]

I notice that from the factory that they only weld the 1.5" tube on two sides. Normally the left and right. Is this to allow for some flex?