Walter;

Alodine is a (conductive) anti-corrosive surface conversion treatment typically used for aluminum...it is not suitable for steel AFAIK and I wouldn't recommend it here. I suggest you abrade away paint and/or rust at the chassis connection points to a shiny clean surface to assure a good electrical connection, and apply ACZP to encapsulate and protect the connections as you make them, including any adjacent bare metal which would otherwise be susceptible to corrosion again, then wipe away excess, leaving a surface film. This will give long-term protection and peace of mind!

Reference: http://www.sw-em.com/anti_corrosive_paste.htm

Cam; POR and any other anti-corrosive surface treatment like paint, is also non-conductive, so does not meet the requirements for electrical conductivity here.