Have you checked/replaced your rubber flexible brake lines recently? Worn and soft lines will resist pulling the pads away from the calipers when taking your foot off the brake pedal.

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)