The general concensus posted here is never turn volvo rotors -- just
replace them. Now, I'm not sure if resurface is the same as "turning"
since I don't know how much material a resurface removes. A pair
of new rotors goes for about $135 (mail order).

Wheels should be hand-tourqed to 81 lb/ft using a star pattern (if
for no other reason then to eliminate this as a possible cause of the
problem).