Big Red problems!!!

[onixbonilla]

Hi everyone!
My 1303 uses front and rear 993 Big Reds with a 951 master unit. I had discover a very disturbing situation. The car brakes very well but the pads do not retract and mantain constant preasure on the rotors.When you jack the car, in order to rotate the wheels I have to push them fairly hard.
In fact when I drive it slowly and depress the clucth it stops by himself,I can feel the brakes working.
Previously I had the 951 calipers/rotors and have no problem, they turn easily.
The following are some things that I had try but no success yet;
-centralize better the caliper using different washers
-installed some used pads(half the width of the new ones) but once the pads
move farther and touch the rotors they do not retract and mantain constant pressure
Rechecked the pedal assambly brake pushrod, it have completelly free movement
As stated before the master unit is the same 951 used with the 951 brakes with no problem at all.
Anyone had similar problems?
Any ideas?
Thanks
Onix