One of the few deviations from stock that I made on my 56 Merc as I restored it was to add a dual master cylinder with a 7" dual diaphragm power booster. The car is just recently completed but in moving it around I find that the brake pedal has little travel and is rock hard. That's all good but the car stops poorly and the pedal does not feel "boosted" at all.

All brake components are new, the engine makes good vacuum. The vacuum source for the booster is the nipple at the base of the carb facing to the rear and I have used 1/2" hose to connect to the booster. The valve that the hose hooks to on the booster works correctly .

I was wondering if an incorrectly adjusted push rod (between booster and master) could cause this conditions ? Any ideas or thoughts are welcome.

Pete