brake rebuild kit question

Correct, it was bleeder thread to be blamed. By the way what's the correct method to remove the brake piston for future reference?

Compressor is best - just make sure you put an old brake pad or small bit of wood in there to catch piston.
If you cant get it that way pump up the system a bit, add some fluid (blankets etc over paintwork )and use it to slowly get it out ,
lastly use grease
Also dont do it inside unless its your garage

So there's no kind of padded pipe wrench to grab and wiggle it out, eh? Seems like there ought to be.

Dont know if they exist gc - but i have never seen one
Regular inspection and maintainence and you will be fine
Dont go too tight with the bleed nipples