Aah but dont relax just yet, you need to grind all that back to bear metal if possible, then zinc primer then etch primer/metal primer, painting where appropriate and then treat with dinitrol or waxoyl to stop it coming back (on areas unseen such as the parts which sit underneath the sills.
Zinc primers do not work, plus all the so called rust converters
trust me
![Dk :dk: :dk:](/styles/mbclub/smilies/dk.gif)