needing list wisdom (again) sticky brakes

[Livolsi, Stephane]

the patient is my 86 5ktq sedan that I am rally crossing tommorrow  
 
Recap:
last July I took this car on a 1000km holiday. performed flawlessly - no
problems at all
on holidays, I found the 88 5ktq avant that I bought and have been
driving since then.
parked the sedan in august.
 
Rally cross came up and I want to go, so fire up the sedan.
Worried about passing tech so got new rear calipers and rotors (ok, i
should have done this before holidays, but...you know how it goes)
Installed the calipers and rotors, and completely bled the system,
except for the front driver (bleeder screw is busted off). Used a liter
of fluid so we must have got the whole system, right?  FWIW, the brake
fluid that came out looked pretty clean.
 
Anyhoo, the car now feels...'heavy', like something is holding it back
Side note - this car rocks!  Feels like it has much more power than the
avant and with all the suspension work I did before parking, it is nice
and tight, handles well, pulls to 1.4 bar no problem.  AAMOF, I toasted
some 'rice' last night on a test drive.....heh.
Ok, back to the issue, it feels like something is binding, holding the
car back.  Originally suspected the center diff was somehow locked, but
last night confirmed it isn't.
When coasting in neutral, even going down a relatively steep hill the
speed drops off fairly quickly, as compared to the avant I am used to
driving.
I am certain the car didn't feel that way before being parked.
Ok, suspect the rear brakes, sure enough after a good drive, the right
rear rotor sizzles when snow is thrown on it.  The other 3 melt the
snow, but don't flash into steam.  Right rear is sticking.  Why then,
can we jack up the right rear and turn the wheel by hand with relatively
little resistance?  Any ideas?  Could the master cylinder be making it
stick only while driving, but releasing when parked.?
 
Last chance to fix this is tonight, as we have to leave at 7am tomm for
the rallyX.
 
TIA
 
Stephane