Brake Pads or ??

[David 23]

I have Stoptech Big Brake calipers with floating rotors on my 911 hot rod. The pads are Stoptech Sport as was supplied with the kit. On the track and canyons with nice hot brakes they perform very well, nice bite, etc. However once they have cooled a bit, like street driving, etc. the lower the speed the less the brakes seem to bite. Pulling up to a stop light it almost feels like I am on ice. I can't push the pedal hard enough to lock the wheels.
I have 25k miles on the brakes, however the last 18mos. the car has not been driven (new engine build). I don't recall this being a problem during those miles. Is this a pad selection issue, or something else going on. Thoughts?

[icarp]

porterfeild r4s is my fav pad compound , in all my cars and customers as well

costa mesa cali , i think

Ian

[aoncurly]

You should check your brake booster. Mine was faulty, but really couldn't figure it out for a few years. Something just didn't feel right during this time, but finally one day it felt like I was on ice and almost went through an intersection trying to stop. Took it to a shop and they said there was fluid inside my booster (it is supposed to be dry). Replaced it and all is well. They are expensive - mine was rebuilt, and it's still a lot.

[icarp]

It sounds like the pads installed now are for track days and racing.
They tend to have very little bite when the brakes are cold .
Heat them up and they are great .
The R4S is the best of both worlds , good cold and fantastic hot .
If the booster has a seal leak that would create the same behavior.

Ian