Brake issues

I have a 1979 Vette and I have an issue with the brakes. At one time I
had brakes and I had all new pads put on as I was having the entire
car serviced. I put a new left front caliper on and I had good brakes
for about two to three months. I drove the car to Virginia to put it
in my families garage as I was getting deployed to Iraq for one year.
As I was driving the car to Virginia about 200 miles into the trip I
went to pull off and get gas when the brakes failed s the pedal went
to the floor. After my deployment I brought it back home, in DE, where
I replaced the master cylinder, and the left front caliper and I bled
all the brakes and bench bled the master cylinder and I still am
unable to get pedal. All calipers are expelling fluid as I bleed them
and I realize that there are 2 bleeders in the rear calipers. I am
having issues with the fluid coming out of the new caliper but the
flex hose has fluid coming out before I put it on the caliper and I
can not get any pedal at all. The brake light continues to stay on and
I checked to see if I had a bad booster but it seems to be alright as
I removed the hose and there is suction and the the brakes get hard
until I put the hose back on and the brakes go soft again. Can anyone
help me with this issue? Any ideas? Thanks. Brian