Gazzar Posted September 17, 2012 Share Posted September 17, 2012 Quick one, I've a rear tub which has a fair bit of alu corrosion where it was mounted to the rear crossmember tabs. What's the best way to tackle this? Once refitted the corrosion will be invisible, and the back will be plated so there'll be minimal strength issues, but is there a way of repairing the damage? What kills the corrosion in the metal? I'll be putting a barrier material between the steel and the alu on refitting. Would hot alu spraying do the job? G. Quote Link to comment Share on other sites More sharing options...
Snagger Posted September 20, 2012 Share Posted September 20, 2012 I found that Jenolite seems to work reasonably well on aluminium even though it's meant for steel. But if the tub cross member is rotten, the only option is to replace it. LR sell them for the Defender and it's a direct replacement. Craddock also sell a folded aluminium strip as a replacement, but it doesn't have any pre-drilled bolt holes or the spot welded diagonal braces at each end where it secures to the rear wings. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted September 20, 2012 Author Share Posted September 20, 2012 Thanks Nick, I don't think the bar is too bad, it's just the end panel. Most of it it is invisible, so I may just use filler. I was just wondering if there was anything more "natural" as a solution. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 20, 2012 Share Posted September 20, 2012 The corrosion is caused by the steel of bracket and bolts on mine. Galvanised bolts would be best if you can get them? Stainless steel still causes corrosion! So my latest fix is to wrapp washers in electrical tape and brackets in gaffer tape. Anything to keep them electrically seperate. But like all heavy corrosion, I am begining to suspect the only fix is to cut it out? But there wouldn't be much of my truck left I'll try the jenolite idea. Sounds a good tip! If I can get mine cleaned back to bare metal I think etch primer would be in with a chance. What has slowed the back end corrosion is some ally sheet placed to stop road muck from throwing up into that area (stopped it going down the back of the tank as well) Quote Link to comment Share on other sites More sharing options...
tugboat Posted September 20, 2012 Share Posted September 20, 2012 I always use Duralac chromate paste on fastenings and metal mating surface on my boat's deck fittings but if you search yachtie forums you'll find there are differences of opinion on this too. The corrosion rate depends quite critically on the actual alloying content of the aluminium in question and in this respect, by some accounts pre 1980 Birmabright seems to score better than the later LR aluminium body materials. My experience is that Duralac helps a lot on stainless to aluminium connections where frequent, sometimes constant, sea water drenchings are the norm, as well as on 316 fittings to aluminium castings in sea water cooling circuits, but I wouldn't dream of having anything but perfect electrical insulation between aluminium and copper, bronze etc. Insulate with plastic pads or washers wherever possible I'd say, and always use Duralac. Quote Link to comment Share on other sites More sharing options...
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