83 300D camber problem

[randych]

First of all, thanks to everyone here for their vast MB knowledge. I've been a lurker here for years, and have always been able to find answers to my many questions by searching... until now. Here's my situation.

My 300D front tires had terrible wear. The outside tread looked almost new, and the inside tread was worn down to the steel belts. Not good. I got new tires and immediately took it to the local Firestone for alignment. As expected, the camber was way out of whack (-1.2 and -1.1, with the range supposed to be -0.3 - 0.2), but Firestone said they can't adjust it. They said I needed to buy a camber kit.

After searching here I suspected that the problem would be with the UCA bushings, but my local mechanic checked them out and said that they're in good shape. Although he thought the idler arm might need replacing.

Any other thoughts? Did the Firestone guy just not know how to adjust this car? What else could be causing this unusual tire wear?

I should also mention that this is a relatively recent issue. The last few sets of tires had mostly normal wear.

Thanks for any help you can provide.

Randy