Inner wing repair

As I write this on eclipse day, the Alfa just failed it’s test The MOT test forbids any holes within 30cm of the main structure. And guess what the tester found?

Once I’d got over the shock, it turns out the rot isn’t too serious. It seems there is a water trap where the front inner wings meet the top of the main chassis leg. The corrosion is located just above the lower wishbone mounting bolts, and is visible from the wheelarch. Further investigation showed the the engine side is OK, and the chassis legs appear sound.

I guess this must be a stress and corrosion weak point, so you might want to give your car a good prod here. Further investigation suggests that the rot was caused by a combination of a leaking washer reservoir, together with extra stress on the chassis caused by partially siezed wishbone bushes.

It seems to me that this part of the wing isn’t particularly structural – the metal is incredibly thin! The strength is provided by the main inner wing and chassis leg, both of which are much more substantial. Still, arguing with the tester was never going to get it through…

I raised the car on the chassis, and removed the lower wishbone bolts. This is a faff, as you need to drop the exhaust off as well, but it allowed the suspension to be moved out of the way. Take note of any camber shims here (my car has none).

The base of the wing panel is spot-welded to the chassis behind the suspension mounting points. I chiselled the remaining bit of corroded panel from the chassis rail to allow for a good repair. Then it was just a matter of cutting a new repair panel to shape, drilling the holes for the wishbone bolts, and welding it into place.  

Some zinc primer, white stonechip paint, followed by a good coat of WaxOyl should keep the rust at bay. The metal I used was slightly thicker than the original. This will hardly affect the camber at all, but it has altered the tracking. I will live with this until I overhaul the top arms, when I’ll set the camber, castor and tracking all together.

The tester was happy with the repair, and the car is back on the road again. Yay!