95 concorde brake issue

I receintly replaced the front rotors and pads on the 95 concorde. When I was done I pumped up the brakes however they never got hard. I replaced the check valve on the brake booster (because it was cheep) however this did not change anything. When you turn off the engine and you press on the brake the petal goes down, then you pump once and the petal is hard. I was always taught if the master cylindar was bad then the petal would go down all of the time. Also if the brake booster is bad then the petal would be hard with the engine started (no power brakes). On this the petal is hard with the engine off however as soon as you start the car the petal goes all of the way to floor. We blead out the brakes however it did not get better. This car has ABS and Traction control. does this make any difference? I also looked at the calipers with the wheels off and they are all moving ok. checked everywere and no leaks. Help me I am stumped.

if the master cylindar was bad then the petal would go down all of the time..
Well, yes, but an MC can go bad in other ways, too, and produce different symptoms. I think you should replace the MC.

Its possible that when you pumped them up you pushed the pedal all the way to the floor. The seals in the master just went through all kinds of debris and possible are ruined causing your symptom.

Make sure there are no leaks anywhere. If you have rear drums make sure the rear brakes are adjusted up and that the wheel cylinders are not leaking.

no the rear has disks. I guess that I will have to replace the master although I still cannot see how it would be hard if the engine is off

The booster and the master are two different things. The booster relies on engine vacuum to provide the assistance. When the car is running there is plenty of vacuum and the brake pedal is much easier to push down. If the engine is off the is no vacuum and there is no assist from the booster which makes the pedal a lot harder to push down.