Thanks for the responses.
Originally, I bled the front two calipers, passenger side first.
Then I pumped fluid from the caliper back up to the master cylinder thinking I had an air bubble trapped somewhere.
Then I replaced the master cylinder, bled the master cylinder and then bled all calipers starting from the rear passenger, then rear driver, then front passenger, then driver side.
Then just for the fun of it I pumped fluid up all the lines in the same order.
Brake power booster problem?... That sounds depressing but thanks for the suggestion.