I haven't bled brakes for 40 years or more and my memories of that are not good. I just read some internet posts about it and am curious about the vacuum bleeders. Also, about "bench bleeding" a new master cylinder.

Since I won't have any reliable help to bleed the system, after adding the dual master, I like the sound of the vacuum bleeders I've read about. But, there are also some bad reports about them. Looks like you either love them or hate them. Any comments out there?

As for a new master cylinder bench bleeding, is there any reason you must do it in a vise? All the instructions say to do it that way. Why not just mount it, install the bleed kit, and use the pedal to bleed it? Seems easier and less mess.