Nissan Repair: brake problem, caliper pistons, brake job

Question
hi after having my front disk pad replaced one week later i have no brake on the peddel.i have bleed the brake system several time's and checked the vacuum on the brake booster,the peddle is hard when the motor is not running but when i start the motor the peddle will go all the way to the floor with only a very small amount of brake.could you help me with this problem.
cheers Chris

Answer
Chris,

The seals in the master cylinder have probably blown from having the brake job done.  Nothing anyone really did wrong.  When you bleed the brakes or compress the caliper pistons the pedal has an opportunity to travel lower than normal.  When this happens the seals usually fail.  It takes a week or more so that is what it probably is.  No pressure in the master cylinder, when the engine is running.  Feels almost normal when the engine is off.  I say it is the master cylinder from my past experience.