Had my front end up to inspect things before winter hits. I think most are aware of the support braces that can fail on a W126.
http://www.peachparts.com/shopforum/body-repair-restoration/293938-cracked-frame-w126-owner-alert.html
Just a heads up for the new guys. Today I found that while the supports are still sound, my frame has developed a nasty hole and or crack about 3 inches behind the support. This was not visible this summer.
I will be removing as much of the undercoating as I can and see how bad it really is. Luckily I have a friend that can repair the frame. Scary stuff!