I find that hydrovac units were widely used. I have one on my Speedster and worry about it sucking brake fluid into the intake.
In any event I tripped over a pretty nice writing on Hydrovac units.
http://www.stovebolt.com/techtips/bendix/erickson/
Happy Trails, Murray
In any event I tripped over a pretty nice writing on Hydrovac units.
http://www.stovebolt.com/techtips/bendix/erickson/
Happy Trails, Murray