Make sure you are pressing directly on the center of the piston -- if you pry or push on the edge, you can get it cocked in the bore and it won't move until you tilt it back.
The last time I had one that stuck I ended up rebuilding the caliper -- idiot PO (or his mechanic) put new pads on a rotor that was too thin, they got cocked and roasted the dust shield. Lots of dirt and corrosion around the top fo the piston, wouldn't go back in. Piston cleaned up fine,though, still works great. Big PITA though.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
Last edited by psfred; 07-20-2003 at 08:51 PM.