Touchy Brakes

[AMXguy]

After an ordeal to find a new master cylinder for my '70 Challenger I got a new Raybestos one and got it on. since I had it out I put a new set of brake lines from Fine lines and detailed everything out to look nicer.

Before my master started leaking  (  two year old twin to the new one I installed )  my factory power disk brakes were PERFECT.  now they work very nice, not grabby, but they are very touchy. with a soft foot you come to a quick clean fast stop, but far less forgiving than what it used to be or what I'm used to on other cars.

What could it be? I readjusted the rod between the booster and master,  that's the only thing I can think of.  I can live with it as is, but I liked it better as it used to be.

[Chryco Psycho]

is the master a larger bore , do you have the old master around still ?

[AMXguy]

This is the larger bore, and I don't still have the other one but it looked identical and was the same brand.

As I understand it all disc brake big block cars has the larger bore, or maybe it was disc brake R/T's ?  anyway I'm 99.9% sure my other one was the same bore. 

[Madmaxx]

maybe off on this one..but...try unplugging the vacuum from the booster..of course it will be much harder to push but see if its still the same touchy-ness(lol)..i had a 69 amx (of all things) and the previous owner put on a rebuilt m/s/booster combo..brakes were very touchy..it would stop perfect with a light foot..but any sort of a non-light foot it about sent you thru the windshield and locked em up....i jacked with that thing for a whole summer..i finally unhooked the booster and drove it..it was not touchy at all just hard to push....sooooo i put on a another rebuilt booster and it was the cure?...the previous owner was p!ssed..lol..worked for me maybe worth a try?..good luck!!