80series Rust

Its possible brake fluid has leaked down the firewall lifted the paint, and allow rust to set in.
I would keep on looking, their are plenty of rust free ones especially in the country.
Cheers pete

Don't know if it's common, but my 92 1HZ 80 series has not one speck of rust anywhere on the body or chassis.

I'd cross this one off the list and keep looking, unless the price is exceptional.

Our 97 model is also rust free.

G,Day Woody, The most likely cause of rust in the described area is when the plennum chamber { box section under windscreen wipers} gets leaves and dirt in there which can fully or partially block the drain holes hense the moist dirt and leaves create corrosion inside the plennum that creaps out through the seam. Cheers Troopytrek

Careful...the 80 didnt have rust from the factory and very few are rusty...might be a 1 off, but last thing you want is to have to chase that stuff round the engine bay....look elsewhere.
Andrew

As madfisher has stated maybe it has had a leaking brake/clutch slave cylinder leaking at some stage and has ran down either internally of externally and has striped off the paint and kept going from there. As said above I'd be walking and let him have the headaches of it. There are a sh#tload of 80 series around and especially petrol 4.5L's you tell them how much you want to pay esepecially if you are buying from a yard. One been sitting out the front of mazda hear in Penrith for nearly a month now and still sitting there, I had a quick look one arvo and is in really good condition and sales man just about bowled me over thought he had a potential sale I said na just bought the prado just tyre kicking he then proceeded to tell me they cant shift the petrol cruisers and patrols as people dont want them cause of fuel usage but gas is another way for saving some $$$. Walk, better to wait for a good one. Where you located ?? few for sale (turbo diesel factory) around the Sydney areaon the web. Regards Steve M