Power brake problems

[mclairmo]

Is the booster new? May want to take a Mityvac to it and confirm that it is holding vacuum and not leaking. Also, does the master have to be sealed well against the booster? I remember seeing master to booster seals/gaskets out there. Also, is the engine pulling enough vacuum at idle to operate that booster? I would take a vacuum guage and hook it up to that T you have and make sure you have sufficient vacuum. Also, confirm that you have the T hooked up to full manifold vacuum and not some other type of vacuum source such as timed manifold vacuum or ported vacuum.