Brake Booster Failure?

[stÖrmy]

started a topic about this a while ago but cant find the thread. here is what happened...

left car on a hill in backyard with hydraulic handbrake locked UP for about 2 weeks. This had caused the master cyl to fail and die and leak everywhere. I put another master in and now she doesnt leak at all.

Now im having issues bleeding the brakes, long story short its like there is infinity air in the brake lines. The hydraulic hand brake just taps into the rear brake lines, when i put my foot on the brake pedal, and then pull up the hydro hand brake there is resistance like normal, but if i lift my foot of the brake pedal slightley but still leaving pressure on the pedal the hydro handbrake pulls all the way up and makes a loud whooshing noise, when i put my ear on the master cyl it sounds like there is either air or fluid being pushed back into the master cyl?

can anyone advise? 2 workshops have tried finding the issue but have had no luck, for some reason i think my booster has failed but i didnt change it when i done my master because people advised that boosters hardley ever fail and i shouldent waste time doing it...but?

[stÖrmy]

any ideas guys really need some input on this