Trying to bleed the brakes on my 88 Iroc, new calipers in front, rebuilt calipers in the rear, the front bled fine, can't get anything out of the back. the pedal was hard after bleeding the front, acting like the system was fine. I checked the line to the back for clogging by air pressure and it was ok. what am I missing? Thanks.

 

when bleeding the whole system you want to start with the caliper furthest from the booster, ei, the rear passenger side. then the rear driver side, then front passanger side, then front driver side.