Hans, no, I don't have service manuals. I was going to see if I could find the range on Norge parts microfiche at our appliance parts dealer. If I can find the part number of the bake element, it could help in seeing if there was a substitution to a sealed rod type bake element.
I don't know if it would help with the rust you mentioned in your range's ovens, but I keep heavy duty foil on the floor of each vintage oven I use. It is safe as long as you keep it away from the element connection location and as long as you use it in ovens with sealed rod type elements. Foil protects the oven floor from spills and takes the heat stress off the porcelain under the bake element. Needless to say, if the oven is a self cleaner, I remove the foil before the cleaning.
I don't know if it would help with the rust you mentioned in your range's ovens, but I keep heavy duty foil on the floor of each vintage oven I use. It is safe as long as you keep it away from the element connection location and as long as you use it in ovens with sealed rod type elements. Foil protects the oven floor from spills and takes the heat stress off the porcelain under the bake element. Needless to say, if the oven is a self cleaner, I remove the foil before the cleaning.