Also, don't use a screwdriver or some other prying device and leverage against the disk. You can easily put a wave/dent on the disk and then have to replace it as well.
I use large channel locks and grab the edge of the backing plate for the pad.
Larry is absolutely right: Do one pad per caliper at a time. I know from first hand experience: A stupid and costly lesson. My neighbors still remind me of the expletives they heard from my house that afternoon!
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)