there are three pipes that come out of the lock/unlock vac pump: Drivers Side Door, Passenger Side Door/Rear Hatch and the Fuel Door. There is a " T " in the line behind the interior panels right next to where the fuel door with a wersbo fitting there. I'd recommend just getting some new airline from a shop that works on semis and replace the part that cracked. The pipe you'll need is what they would use for behidn the dash for the air pressure and brake gauges. You may have it sealed up with the superglue but it could have ran down from the crack and into the rest of the system and is blocking the pipe. I don't know why it would want to try to stay locked but perhaps it has enough vacuum in the line or something. Hopefully, you didn't get any superglue into the pump and bugger that all up.

Hope you get it working right.