To those who are unable or unwilling to take studious care of the chassis this is a real concern. I regularly inspect particularly after each winter for the slightest sign of rust streaks which shows up well against the black underseal. Such areas on chassis as mentioned above and usually where extra welded strengthening has been performed on chassis get treated with ACF50, indeed any gap does. For cavities and box sections with access I also use aerosol wax oil available clear or mixed with black paint, tenacious stuff given how difficult it is to get off your hands. Note the 3.7 Roadsters, and maybe the 5 link ones more so, with need for greater strengthening likely require greater vigilance. Mark's pictures below.
![[Linked Image]](https://i.ibb.co/chspQJct/IMG-4154.jpg)
![[Linked Image]](https://i.ibb.co/21RsYKQw/IMG-4195.jpg)
The introduction of electrophoretic coating after chassis was completed was just a cost saving over galvanising IMO. Sadly the ensuing corrosion is unlikely to be limited to one or two cars.