Brake Problem- Need Help

My husband has been working on his neice's 96 Corolla. She has been having problems with the brakes. My husband changed the master cylander twice and the booster. Calipers are new. Since he has tried everything else he wanted to know if it could be the block where all the lines go that is bad. He already did a pressurized check and it was fine 10psi.
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the part that goes to the block is just an empty space. The booster works off of vacuum pressure from the intake manifold (the pipe that goes from the booster the the engine is a vacuum line) when you push the brake pedal, the vacuume of the engine helps you to push down the pedal(go to a car that has working brakes, and with the engine off, press the pedal a few times, it will become really hard. That is because there is a little vacuum left after the engine is off, after you use it all up, and the pedal is really hard to push)
Anyway, make sure there is no clog between the booster and the intake manifold, My booster and master cylinder are 10+ years old, thats probably not the problem. Has he tried to bleed all the lines?

On a side note, if he cant figure out what is wrong with the brakes, it might be a better idea to have the car towed to a shop, and have a mechanic look at it. An engine that doesnt work right may not be the best thing, but brakes that dont work right could kill you niece(and whoever else is in the car)

Thanks he already fixed it. It turned out to be the Booster and Master Cylinder
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Ford Interceptor specifications (http://www.ford-wiki.com/wiki/Ford_Interceptor)