Hi All, I have a 1977 Thunderbird with 35,000 act miles on her. I know I have a vacume leak under the dash, the only thing I don't know is what is the best way to figure out where exactly is it coming from I mean which vacume line

 

 

Thanks go-part, that will help a lot!

 

Something you can try, If you use a pair of needle nose pliers and can ,see the vacuum lines, Gently clamp the individual lines . Hopefully one of them will be supplying the line or component that is leaking the vacuum. There should be one line supplying vacuum to the inside of the vehicle. If you locate that line which either comes off the intake manifold or a junction from the intake manifold, remove it and blow some smoke through it , it should exit out the location of the leak.