Galvanic corrosion? D'yer mean electrolytic corrosion? If you can separate the steel from the ally put a gasket between the two or blather the whole thing in shutzy type underseal to try an keep the moisture out of the joint.
basically what i wanna I was trying to get at is, hopefully if i get my landy tomorrow is what should i do to all rust affected areas (ali/metal) prior painting it.
I know I can paint on top of it but i would prefer preparing it first so it does not just carry on corroding under the paint.
Phosphoric acid will kill ally corrosion dead. As it's acid it dissolves the oxides and nitrates and other mineral salts, as soon as it hits good ally it stops as it anodises ally on contact. This can then be painted over without the need for etch primer or other special coatings.
Problem is, how to get hold of Phosphoric acid without resorting to distilling gallons of Coca Cola sugar free...
get a tub o brick acid from b n q. its he same stuff as hydrochloric acid so it is a chemical deruster. it also kills all the oxiuizing agents in alloy an it looks good while its fizzing. it also cleansd the ally up nice but it meks yer fingers turn green and itch