brakes go to the floor when car starts.

[megaladon6]

12 is the minimum to run vac assisted brakes i think, 14 is better.

 

[Bonnewagon]

OK,sorry I missed that. Are you keeping the vacuum pump on the car? If not then what you need now is a vacuum reservoir in the line before the booster. It accumulates vacuum and is good for several applications of the brake pedal without the motor running at all. It has a check valve just like the one on the booster.Cams that rob vacuum need these to supply the booster . Moroso,Crane,Summit,and some others sell them,about the size of a coffee can,but I get them at swap meets for $10.00.