Brake booster not releasing?hmmmm

I just installed a 4 wheel disc brake setup from PST and everything works but when I push down on the brake pedal it does not come back up unless I lift the pedal with my foot.Without lifting the pedal manually the brakes are on solid.The booster is holding vaccum and the push rod is not hitting anything.Could it be a brand new booster is bad?Has anyone seen this before?