I just completed a 4 wheel power disc conversion from 4 wheel drum non power on my 69 and finally got the brakes bled after many long hours of trying everything. I have good hard pedal and no air from the bleeders but when I hooked up the booster and started the car the pedal got real soft. I drove it around the block and it would stop ok but the pedal almost went to the floor. I bled some more and got no air but still soft pedal when car is running. I have some pedal at idle but when RPM's are up it goes almost to the floor. I put a vacuum gage in the hose going to the manifold and at idle I got 10 inches, with more RPM's it goes down then up to 18-20 inches. How do you correctly check to see if I have the correct vacuum which I know is 18 inches? Any help will be greatly appreciated. Jack

ck master cyl. rod length, may be off, they have had problems with these in the past, Rob

The brake booster must control pedal return, don't use any rubber bumpers or return springs on the pedal, make sure the brake light switch is not restricting full return. The pedal should be closer to the floor than it was with manual brakes, 5.5" from bottom edge of pedal to floor kickup, - the area of the floor where the pedal would hit if it went all the way.

http://www.pozziracing.com/brakes.htm#Converting_Drums_to_Discs

I'm Still Having Problems With The Booster Connected. I Readjusted The Rear Parking Brake At The Caliper And Measured The Pedal Distance. The Parking Brake Was Not Holding Before But Now It Is. I Drove It With The Booster Disconnected And Had Fairly Good Brakes. As Soon As I Connect The Booster Pedal Goes Almost To The Floor And It's Real Soft. Help!! Show Season Is Almost Here.

Someone suggested using a vaccum canister to increase my vaccum to solve my problem. The canisters from Sumit is suppose to double the vaccum but I have 15 inches of vaccum at idle. Has anyone used these canisters and if so did it help?