the tube nipple to the right of the brake booster tube

Has there been any trouble with leaks at the nipple to the left of the brake booster tube outlet? And what does this nipple/tube feed vacuum to? I bodged up the brake tube with "the right stuff" and had no problems, but after a single run something let loose and codes are back. REALLY don't want to disassemble the SC. (not my pic BYW).

 

it feeds vacuum to the super charger bypass diaphragm . the round black thing just above it .
i have seen these diagrams fail . and leak vacuum . but its not the most common form of vacuum leak . just a possibility .
easy to check . run a test pipe to the diaphragm and suck on it to see if its leaks .

my guess is that the "right stuff " has failed because its the "wrong stuff "
you need to replace the oring inside the coupling .

 

thanks i'll test the bypass tomorrow. car is high miler so failures are possible. yeah . . . i hate bodge fixes. just so much ancillary parts to the engine getting in there and mucking about is no easy thing. fun fun fun.