Oil filter change OR valve job you could have knocked one loose. However as long as the brakes feel normal, you can probably rule out the major vac line off of the pump.
Pick up a mityvac, those things are worth their weight in gold while troubleshooting these cars.
I THINK that there is a yellow vac line going into the firewall connected to the central locking system. It is easy enough to take the passenger door panel off and stick a golf tee in the lines (or pull vacuum with a mityvac), see what works and what doesn't.
Oh, and welcome!!
