Victor,

My 240 doesn't have ABS, my 850 does. ABS through the aid of sensors at each wheel will activate when very hard braking is applied. It simply prevents the wheels from locking-up by responding very quickly and in-turn pumping the calipers till a complete stop. The logic is that without wheel lock-up inturn preventing a skid, a driver can continue to steer the car out of a potential problem, always giving the driver as much control as possible. This feature will go largly ignored with day to day driving, but will come to life the first time you slam on the brakes. If you have replaced your pads in the past or any other maintenance work on your '92 brakes, there is no reason why you can't continue doing the same on a car with ABS. Bleeding the system however is a little more work as the master cylinder (with attached control module) requires more care in fluid replacement. Are they harder to maintain? Generally no, but you do have additional parts that can fault and it's not uncommon to hear of sensors being replaced. Our '94 850 has never had a fault with the system and continues to operate trouble-free. You may be interested to know that the "Tracs" feature on newer Volvos uses the ABS hardware to eliminate wheel spin from a dead start...