It may take a bit to bleed out the air, as you're experiencing. (Think brake bleeding....)
Is the I.D. of the new braided hose the same as the old? I'm just thinking about the volume of fluid displaced from the a reservoir & hose into the preload piston.
The piston has a fixed distance it can move but the reservoir and hose can only hold so much fluid. The braided hose *should* expand less outward, and hopefully no more in length than the OEM when pressurized. Being shorter may mean less fluid overall for the piston is all else is the same. (The old volume / pressure / area equations..)