Thread: Surface corrosion?

Do you mean the patch in the bottom left corner of the frame, on the lower rear side skin? That's aluminium as all defender skins are, so I don't think it's much to worry about. Looks like a scuff has broken part of the paint and caused surface corrosion on the aluminium, causing the paint to bubble. Looks worse that it is. Aluminium corrosion is very stable and doesn't advance much at all, it just causes the paint to bubble and look nasty. As far as I know the only really worrying areas for rust on a defender are the chassis and bulkhead. The door frames can get quite bad but can be replaced relatively easily.

The picture is not quite that rosy. Aluminium will corrode badly if in electrical content with another metal that is more electropositive (most common metals except zinc, but especially copper) and both wet with the same water or electrolyte. To avoid corrosion, aluminium should be electrically isolated from other metals - and this is not always the case in Landrovers. Particularly bad is the bottom of the door skins if water is allowed to collect where the steel frame is in contact with the skin.

That corrosion on the curve does not look significant, but if left untouched could spread and lift paint.

Not applicable here, but note that over the years the Defender had more and more of the aluminium panels replaced with steel, but I don't think there was much in 2000.

Originally Posted by JDNSW

The picture is not quite that rosy. Aluminium will corrode badly if in electrical content with another metal that is more electropositive (most common metals except zinc, but especially copper) and both wet with the same water or electrolyte. To avoid corrosion, aluminium should be electrically isolated from other metals - and this is not always the case in Landrovers. Particularly bad is the bottom of the door skins if water is allowed to collect where the steel frame is in contact with the skin.

That corrosion on the curve does not look significant, but if left untouched could spread and lift paint.

Not applicable here, but note that over the years the Defender had more and more of the aluminium panels replaced with steel, but I don't think there was much in 2000.

Yeah I suppose that makes sense actually... but even in that scenario, I always thought that with aluminium oxide pitting happens far less severely and rapidly than in ferritic metals?

Having dealt with exactly this sort of corrosion on my Defender 130 I would immediately sort it out. It's not going to get better by itself and it's not going to stop. Something has caused it and you need to intervene if you want to save yourself a lot of pain and money down the track. I don't know what's behind those panels on a 90 but I'd be pulling off whatever lining is there and having a look at what's going on.

I also had bubbles like that on my Series IIA doors from electrolytic corrosion, it's very hard to sort out if it goes too far. I had to remove the skins entirely and spent a lot of elbow grease getting them back to a good surface then sealing them. The corrosion will come back but I bought myself a few years.