Brake System Rebuild

[76square]

Time for a complete rebuild of the braking system - planning to replace many components. I have three '76 C25 trucks - two have the J55 heavy duty brake option, the other doesn't (I guess it's called the "standard" braking system). I've noticed the heavy duty brake option uses a slightly larger master cylinder and power booster unit than the standard brake system comes with. Braking action seems better with the heavy duty option although I realize there are many factors that might contribute to this. Question: can I replace the standard master cylinder / booster unit with the heavy duty version? Would this affect anything? How about the proportioning valve - do these things wear out? Any help is much appreciated!

 

[GTME94]

I don't know about system performance but the std system had different brake line sizes than my heavy duty system. The parts place gave me a std master the first time and it wouldn't fit. Took it back to get the right one and it worked.

The heavy duty has larger pads and shoes that probably help give a better feel.