How do you know there's no air in the abs....without bleeding with the factory drb unit it's just about impossible to get air out of it with a conventional bleed.....the fluid will come out of the caliper air free but it will still be trapped in the abs. About the only ways a pedal will sink is with a faulty brake booster or air in the system.
Sent from the Dark Side using only the Force.
Before you judge a man, walk a mile in his shoes; after that, who cares?! He's a mile away and you've got his shoes!