My brake System is mostly out of a 91 saloon, using its brake servo and dual master cylinder, but with 7 ½" discs on the front with 10" wheels.

Problem is that I have 19" of vacuum, and when I pull the hose the vacuum escapes, telling me that the diaphragm must be good, but I have no real power assist.

I'm wondering if adjusting the length of the pushrod would fix it, but don't know the right length, or if there is an adjustment that does not require pulling or twisting of the bracket that is attached to the thick pivoting finger. Can you just turn it?

If that might be the solution, what it the correct measurement/length? And from what point to where? I can't find that in the manuals.