brake booster inop

[Formerly Steve Wilkinson]

The brake booster on my '83 SC has gone tits-up. I never knew it, just assuming that "old Porsches" took a bit of braking effort, but today I traced a carburetor (PMOs) anomaly to the fact that #2 cylinder was running with an air leak, because the booster is plumbed into that cylinder's runner. Detached the brake-booster hose and check valve, plugged the fitting on the intake manifold, and the engine runs better than ever, brakes take no more or less effort than they ever did--obviously I've been driving around with zero boost.

Question: is this probably going to be a matter of finding a leaking hose, or does a failure of this sort typically occur internally inside the booster unit, like a bad diaphragm or something? The hoses in the engine comartment are all new, so the problem isn't there. Anybody else ever had this happen?

Stephan