Get a couple of caliper bushing kits....chances are you'll have to replace the bushings to get the caliper (it's a floater) to operate properly or else the little rubber boots on the bushings are ripped and the only source I know is junkyard (and those are usually on their last legs) or a kit.

You'll find a 10mm deep socket is handy to remove the locating pin for the wheels that also holds the rotor on the hub. You can kludge it with a small crescent or box wrench, but you might also booger it up.

If you're putting the same rotors back on, MARK where they came off so you can put them back on in exactly the same position. And clean clean clean the hubs and back of the rotors where they meet the hubs. The volvo manual says to use a dial indicator on the hubs and check for runout before you put on the rotor, then if acceptable, put on the rotor and again measure the runout again. FWIW, I just cleaned the new rotors and the old hubs and put them together.

Don't forget to thoroughly clean the new rotor surfaces with gas or kerosene and then soap and water.