Welding to the subframe.

[Qmulus]

Theoretically welding might seem to be the quickest, easiest and cheapest route. One would think that it would be easy to just "reach up there and weld it". but just the fact that you are asking here tells me that you have not found someone to actually do it yet. Talk to a local welder and see what they say. Any welder that I know would want that part off of the car to weld it and would want it cleaned and sand/media blasted to clean it up. Depending on the alloy, they may need special rod and heat treating. Then you need to do a little finish work. Ugh. None of that sounds quick, easy or cheap to me.

My advice, suck it up and replace it. In the end, it will be faster, easier and cheaper just to replace the whole bracket. My guess is that you will be able to find the part is readily available and reasonably priced, as they are not a common failure point.

Just my $.02. YMMV.

[911monty]

First off you can not just "weld" the aluminum without knowing exactly what it is. Forged, heat treated or just cast require different welding techniques. Welding will change the metallurgy of the material near the weld from the heat. Aluminum is much more sensitive to heat than steel and can become brittle if not not done properly. Since this is a suspension component it is likely at least heat treated. You also stated that the suspension is being stressed under heavy load. Since the spot that has failed is directly where the control arm is bolted to and is in the middle of the support you can bet the forces are highest there. Now ask yourself, What would happen if this component fails during any aggressive driving?

[rusty69911]

those whole brackets are less than $100 on ebay, I paid that shipped to Australia as mine was missing all together, not a hard job to swap out