Ok. Here’s an update. I looked closely at the bell crank linkage and noticed some play in the pedal when you pull it up by hand. It looks like they may have put the system together and left off one or more of the bushings in the linkage. The 1/4” of play amounts to about 1/2” of travel before the booster moves to activate the master. I separated the booster from the master to see this. I also noticed that the studs that attach the master cylinder have been changed. They are longer and don’t have the taper. Also there is a new looking rubber part around the plunger and the rod looks nice and shiny. I’m thinking the booster has been rebuilt. It has the same patent pending numbers as my spare booster but someone put body filler over the pentastar. Go figure. It’s probaly a parts store reman.

I slightly separated the master and had my friend push the pedal. If you take up the slack first, the rod moves as soon as you push the pedal. It occurred to me that I have not had rear brakes with the old master. You had to push it almost to the floor and the front brakes would grab instantly. It was the same way with the new master until I adjusted the rear brakes shoes real close to the drums. Then they were so close, they would not release good. My front disc would release after a few seconds, but my rear never would. Especially after driving and getting hot enough to expand against the shoes. So now I pull the master off to check it. The first thing I check is for the check valve in the front reservoir. It is not present in the latest reman. I checked the one that was on the car that probably came with the SSBC disc conversion and it did not have one either! I pulled out my NOS 70 ebody to show my friend what I was talking about. You think these guys would know the drum brakes require this to work properly. That is why I had to push the pedal down to the floor to move enough fluid to engage the rear brakes. By then the fronts were taking all the pressure and grabbing hard. When I adjusted the rears to work at all, they were too tight.

So looks like I’m in for under the dash session with that easy-to-reach brake pivot. Lol. I will also have to explain to a parts man at O’riellys why his master will not work on my car. I’m ready for a blank stare on that one.

Has anyone had luck finding a new or rebuilt master for a 70 ebody at any local parts store? I need to check it for the residual valve before I take it home. And I know what you’re thinking. The answer is NO. I’m not using my NOS master on a customers car.