Well here is my dilema. I just got done installing 95 Civic EX calipers, spindles, and hubs onto my 94 Civic Si. I also installed SS brake lines all the way around. I bleed them and had a nice firm pedal yesterday and I went out to the car today and had no pedal at all with the car running. With the engine off I would pump the brakes a few times and the pedal would start to stiffin up. If I held pressure on the pedal the pressure would slowly go away until the pedal was on the floor. I checked for leaks today and found none. Im guessing its the brake master cylinder. My question is, do you think my assumption is correct? Also the car has a 13/16 brake master on it, can I upgrade to a 15/16 as a direct bolt in or do I need to change the booster or any other parts to make it work? Any advice would be helpful.