From your description, it sounds like you found the end links. They're about 1 foot long (about 30 cm) and maybe 1/4 inch in diameter (5 or 6 mm?). The ends of these things have a small ball joint in them which is supposed to swivel. On my old ones, the *good* ball joints moved very freely when I took the links off of the car. The bad ones also moved freely, but there was an additional 1 or 2 mm of play where the ball could move within the socket. The difference between a good joint and a bad one will be obvious when you have them off the car and in your hands.

Do a search of this forum for the words "sway bar" or "end links" and you'll find that plenty of reading material. These things go bad so commonly on our cars that, if they haven't been replaced yet, you should probably just order a set of two and replace them. I got mine for $40 or so at http://www.volvopartsdirect.com/.

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Jim Rothe, '99 S70 T5M,
http://www.jimrothe.com/volvo/index.html