Pontiac Repair: 1995 pontiac grand prix se rear left brake lock up, rust stop, pontiac grand prix

Question
I have a problem with my 1995 grand prix se. It has sat in my driveway for over 8 months. now the rear left tire has seized.  I have replaced the caliper and brake assembly parts and when I re assembled it the problem is still there.  I would appriciate any advice I can receive on this situation. P.S. only parts not replaced were rotor and line in to caliper. and hub spun freely until i bled the brakes and now the brake shoes seem to be locked onto the rotor again.  I tried to break it loose and wore a flat spot on my tire.  again any advice is much appriciated.

Answer
Hi Chris:

Did you replace the complete caliper assembly on this car meaning the piston part and the bridge part where the pads sit in? If you didn't replace the "bridge"  the pads could be hung up in there cauing the wheel to lock up. or if you didn't replace the rotor and ther is a big rust stop on it where the pads could grab hold of it and not releasse that is a possablity. This car is equipped with diaginol braking meanin when you step on the pedal the right front and l/r are paired together. does the r/f tire spin free if so It' not an issue with the master cylider holding the brakes on. the other possability is the perportioning valve in the brake line with the brake pedal released and the whell being locked up open the bleeder on the caliper and then see if you can turn the wheel if so the perpotioning vlave is hanging up keeping the pressure applied to the claiper of possbly the hose is collapsed and it's not allowing the brake fluid back into the master cylinder when the pedal is released. Good luck :)