My newly acquired '940 940 (virtually the same engine/tranny combo) had the same problem preexisting before I bought it. Negotiated $250 off the purchase price and last weekend replaced the clutch. Damn thing looked virtually unused, and an original Volvo clutch, too. Replaced the lot (pressure plate, driven plate, throwout and pilot bearing), put a nice thin even coating of moly grease on the splines and the pilon that the throwout bearing slides over, reassembled, and the screetch is gone.

Observations:

-pilot bearings are often forgotten, to the point that when I ordered a COMPLETE (!!) clutch kit from my local parts house it came without a pilot bearing, and they didn't even have one in stock. Comment: we hardly get any demand for those. The old pilot bearing didn't feel particularly worn, but there is of course a major difference between feeling it with your finger and a B230 running at 2000 rpm.

-Volvo clutch seemed to have metallic particles/threads in it. Replacement clutch doesn't as far as I can tell. Maybe it's good for longevity, but considering the brake squeal probably all of us have experienced with metallic pads I'm not too sure this isn't essentially the same problem. This is a theory on my part, without experimental evidence or even anecdotal evidence to back it up. My car doesn't count, as I did a blanket replacement of everything associated with the clutch.

Bram