I was just reading the post below on the soft pedal and had a question of my own. On my vac booster there is a big vac line going into a white plug that goes in to the booster from the bottom of the carb. Off of that white plug there appears to be another vac line coming off (or in not sure). What is the second smaller line for?? Could it be for the transmission vac modulator??

Thanks, Jeff

 

Can't answer that question...but where is your PCV valve hooked up to, if the booster line is hooked up to the carb base?

 

If the second vac line runs to a metal line down the bellhousing then yes it is for the modulator.

That is if you have a automatic transmission...

 

Starfury...The PCV is hooked to the carb base plate and the power brake booster vac line is hooked to the carb itself on the back above where the PCV line goes into the base.


blue66mustang, I bought the car dismantled and the smaller vac line had been cut about 12 inches from the booster. So I didn't see it come off.I can't imagine a vac line coming off of the brake booster to something else. I would think that you would want to keep all the vacum at the booster and not rob it for something else?? It sure looks like that is what they did though, just don't know where it went.

I can try to post some pics tomorrow.
Jeff

 

I had factory power brakes on mine. And yes the vac takeoff for the trans modulator did indeed come from a split port on the booster. Mine leaked fluid and the modulator line would fill with brake fluid.

I swaped it out for a new one with a dual bowl system and had to splice a "T" into the vac line from the manifold to the new booster. An on my engine there is a dedicated vac port in the intake manifold for the power booster. It is screwed into a threadedport behind the carb.

 

Jeff,
My 66 289 "C' code coupe with PB has a brass block on the aft end of the IM that has the vac taps for the Trans modulator and it also has the large steel tube that feeds the power booster.
It would wise to seperate the PB and the trans vacumn sources, if possible. A photo can be provided.

 

Thanks everyone for the help. I did put in a seperate vac stub in the manifold behind the carb for the trans modulator. (before I saw the smaller cut PB line) I will just put the large steel braided booster line on the carb and plug the old smaller line coming out of the booster that used to go to the modulator.

Thanks again!
Jeff