/diy/ - Do It Yourself

How hard would it be to make an electric servo be vacuum triggered? I have a car from the 80s and it has a whole bunch of vacuum servos and while I believe only one has failed so far the others are bound to go at some point. Not to mention they cost $100 to $150 a pop if you can find one. I would like to just replace them with low-cost Electric servos or solenoids that can be triggered whenever the system pulls a vacuum on that specific line so all I would really have to do is bring power to the servos and use the existing vacuum line to trigger them.