2004 X5 brake problem

[DaveRo]

I had to hit the brakes which blew a rusted line at the rear. I replaced it and bled the brakes. But also the brake peddle moves 2 inches before doing anything, no resistance at all. After moving the 2 inches, the front brakes work, not the rear. When I hit the brakes on gravel, only the front are stopping the car. I ordered a new master cylinder but think it may be the brake booster. Any suggestions? What would cause the peddle to move so easily that 2 inches? Thanks, Dave

[randrews15]

You likely have air in the system. When you bleed the brakes you should run a scanner or other device that can activate the ABS system.