Another Brake query?

[djb222]

Following on from my previous Brake problem with the Master Cylinder for the rear brakes.

Replaced all the seals in the M/S and re installed, bled front brakes .... fine, come to bleed the rear brakes and the pedal is solid, undid the bleed nipple another half turn, still solid (it happens whichever of the rear callipers are bled. Took M/S bake off and it is operating fine.

So, any ideas? My only thought is a blockage or a pinched tube, although can't see anything. I presume the callipers are ok.

Regards

david