I have just completed a complete rebuild of the front suspension on my 71 S model Cutlass. I have removed the drum brakes and put on 11" discs, I bought a new brake master cylinder "factory discs type". While test driving today and break-in of the pads, I had decent brake pedal just not what I was expecting, I may need to bleed them again. My question is, do I need to get a proportioning valve or is the factory disc brake master cylinder enough?

 

Well, the factory used a combo valve, with included a proportioning valve. I would strongly suggest that you duplicate what the factory did.



The factory combo valve was cast iron and can rust internally:



The aftermarket valves are brass, which avoids the rust problem:

 

Thanks, Joe! I will look for one of those.