Do you know of an aliminium welder
Sorry to say I don't, though I would never be sure the job would be a proper fix. MIG welding aluminium is a tricky skill and you may never be sure that the job had been done properly. This is probably the reason that folks seem to have a bit of trouble finding a company to take on the repair.
Obviously there are two conventional ways to skin this cat (sorry to all cat lovers):
- Weld a complete new bracket onto the subframe.
- Puddle aluminium into the scored section to build the thickness back to the original.
Neither of these could be done properly without removing the subframe, which is a pretty major job.
Having just rebuilt the back suspension with the gorgeous purple PowerFlex bushes, I found that the scoring on mine was about 2.5mm and had been done before the current arms/bushes were fitted. You can tell this because the ends of the arms were dirty/rusty and not bright as they would be if they were in constant contact with the subframe.
The scoring is a perfect arc around the fixing hole and is caused, not by the bushes, but by the swing/spring pan arm. I used my Metal putty fix and, in conjunction with the beautifully designed PowerFlex bushes, am completely confident that the job will outlast the life of the car (if not me). Given that the putty is easily as strong as the aluminium, and that the new bushes completely protect the repair, I am happy that it is at least as strong as a welded repair.
Having said all that, don't sue my sorry ass if the rear wheels fall off if you take the same route. I felt that the minor wear on my subframe was insignificant and that the 'putty fix' would more than cure the problem. Your damage may (and probably is) different to mine, so caution is very much advised.
For anyone who has the time, PowerFlexing should be your next DIY job. Once done, you can forget the bushes for the rest of your ownership. Fitting new arms from AR would cost around £350 per side, replacement costs less than that for a full set of PF bushes (Front and Rear) but you do need a bit of time to do the job. I cheated and got my local garage to press the old mounting bushes out of the arms for me. The wishbone and shock absorber bushes can be removed with the aid of a drill and hacksaw. Best tip for refitting is to clean all surfaces and then smother the new bushes with the copper grease provided in the PF kits. Second tip is that the top hat bushes for the wishbone go in from the outside. PF say that instructions are included, but they are very general. Phoning them, I talked to one of their design team and he was extremely helpful.
Good luck, whichever way you jump.