Originally Posted by Graham

I took my 98 E320 to local shop this morning. A lot easier to inspect control arms on hoist! With light and a mirror, shop owner and I could get a good look inside end of arms.

All we could see, was a little surface rust and the wax-like product that had been sprayed in. (Pictures I took with camera make the surface rust look a lot worse than it is).

There is of course no weld inside the arms, just on exterior. What looked like cracks on inside are, it seems, just the edge of the end casting where it protrudes through. The welds looked solid and there was no obvious thinning or penetration of the arms.

Shop recommended I do nothing other than keep doing the annual rust treatment that we do here in Canada. And make sure they apply it inside the arms!

The other important thing, would be to check at least once a year that the drain holes are open, otherwise moisture and salt will no doubt collect down the end where the arms are vulnerable.