Question about MBC

[LTUDSM]

hey guys,
Today i went to check my car for any problems and i decided to try my MBC.I unscrewed (take of) my MBC'S bolt and then try ed to drive my car without a bolt in the mbc.And then my boost gauge showed me,that I'm going 15 PSI.Here is my question:
is it supposed to be like that or there is something wrong?????
Thanks

 

[marcmsj]

is it a spring and ball type mbc? you're not supposed to remove that bolt so put it back on and make sure the spring and little ball is in there.