Originally Posted by Zillon
Well, if they've isolated the problem at the struts, then it's either the strut or the strut bearing.
I'm leaning more towards the strut bearing itself, after removing mine and examining them in my hands, I didn't really find them to be as sturdy as the ones that were in my Scion. Also, there's a lot of plastic content in the strut bearing.
To further my previous statement, I'd place a strong bet on the strut bearings being the culprit behind this noisy mess.
I've been fighting with a slow server here at work causing my uploads to take forever, so I've had some downtime to research the issue a bit. The Volvo C30 and Mazda3 are basically platform twins to our Focus. The front strut bearing, from what I can see in photos, is very similar, if not identical to what is used on our cars.
One big difference I've found, is that our strut bearing is CHEAP in cost compared to the others. The Mazda unit lists for $50(OnlineMazdaParts & Rosenthal), The Volvo at $21 (MyVolvoPartsOnline), while the FoMoCo part lists for only $13 (Tousley). Regardless of cost, the Volvo and Mazda guys seem to be having the same issues, although theirs seem to be at a later point in ownership (not at ~600 miles, as mine has been from).
On the Volvo side, there is an aftermarket product offered under the Febi/Bilstein brand. This might be of interest to some of us.
This is something I'm continuing to look into, I just figured I'd put my thoughts and notes down in a post before I dive deeper.