Brake booster / possible vacuum leak

[Huicho417]

So far every issue I have brought to this forum has been resolved with everyone’s suggestions. I’m hoping this will be the case again.

First, my brakes are not working properly. The pedal will not fully return enough to strike the rod that turns the taillights off. I have to physically pull it up all the way with my foot for the brakes to disengage. It’s almost like the booster does not have enough vacuum to push the pedal all the way up. I had the vacuum hose connected to the intake and recently switched it to the new edelbrock 1406 carburetor that replaced the two barrel. It is a CPP conversion kit so I called technical support and they had me check the booster check valve, which is good. I also checked the booster from inside the car and it seems to be good as well. If I move the car the brakes will stop it but I have to lift the pedal myself every time.

Second issue is that the car idles great, but dies when put into gear. I have to immediately press the gas pedal to get it moving or it will stall out. Not sure if these two issues are related. From my research it points to maybe a vacuum leak, but I cannot find it.
The car is a 67 coronet with 318 and 727 automatic transmission.

 

[pnora]

First off did this all start with the 4 barrel conversion? Secondly vacuum does not make the pedal return.

 

[joe smith]

What kind of shape are the plastic bushings on your brake linkage in?? Mine were in bad shape and would stick..... I believe they make reproductions of them now.

I had to very carefully knock mine out, clean and regrease.. I also acquired a really small ball hone and ran it through the pedal hole a couple of times before re installing the plastic bushings. Night and day difference when I got done...

 

[Huicho417]

The bushings were replaced with the brake conversion. Also, the car has been sitting a long time while I have been working on it. I did not really drive it before the conversion and new intake /carburetor.

 

[steve from staten island]

Have you put a vacuum gauge on the engine yet? Check the bushings as described and return spring .

 

[cr8crshr]

Did you or do you have a Dual Diaphragm Brake Booster? If it is a Single Diaphragm there might be a connection there. Also are you using a single pot reservoir or a dual pot? As suggested above, try those as well...cr8crshr/Bill