is there a way to look in to the cavitys ( spots not to seen by eye ) in the pagoda for rust , my car look rock solid but after these pics from the car jou are restauring 
There certainly are inspection holes into almost every cavity. I have my 280SL on a rotisserie and there are 2 mm access holes to get into nearly every cavity. Many of the access holes have rubber hole plugs that can be removed and replaced. I suspect that all access holes had rubber plugs at one time but many of mine had been removed or lost. Some holes in a completed car would be covered with upholstery or carpet that would need to be removed or at least peeled back to get to the access hole. I have a cheap Centech camera with a three foot probe to look in to each cavity. Resolution could be better but you can get an idea of where the problems are. Some cavities have little or no rust but some areas need attention.
As I have replaced the frame rails and floors on each side I have inspected the inside of the A & B pillars and other cavities. Then I have treated each cavity before I closed the bottom opening. Then I use the access holes to spray the inside of the areas that I just welded closed. For rust treatment in those cavities, I have been using a rust encapsulating product from Eastwood. "Eastwood Internal Frame Coating, Item #12515Z" This is in a aerosol can with a special 360 degree spray nozzle on 24 inch plastic hose to get into the cavities. I am certain that there are other similar products to do the same job.
I am currently working in the passenger side front wheel well to replace the reinforcing strut and deal with other rust areas. I am inspecting and treating the cavities in that area as I go. I realize I cannot get to all of the rust but I am trying to do what I can do.
I admire the great work that Joel is doing on his project car. I wish I had the time and skills to do my car to that level.
Howard
71 280SL 4-speed
