Hey! From your sig I can tell you're referring to your Portland. I ride an '06 Portland.
I heard, but have never been able to confirm, that they re-routed the rear brake cable starting in '08. But this may help if what I've heard was wrong.
On my '06, there's an S-bend in the piece of housing from the bottom of the chainstay to the top of the rear caliper. Apparently no-one told the Trek engineers that S-bends like that are a no-no. The cable tries to accordion the housing rather than pulling through smoothly and cleanly. That brake always felt mushy, never positive like the front one does.
Hey TSL! Yup, I love my Portland. When the "Whats your ultimate commuter bike?" thread pops up, I have to resist telling the world that I am riding mine. Not much that I would change about it.
When you say "S" bend. Are you saying that your rear brake cable runs along the bottom of the chainstay? I can tell you that mine runs down the 10 o'clock postion on the down tube into a stop (near the BB), through a housing to the top of the chainstay at another stop(the other side of the BB), bare cable to a stop (again on the top of the chainstay near the brake) and then in housing up to the caliper. I would not call the last bend on mine an 'S.'
So, maybe the did re-route the cable in '08.
I will tell you that I have wished in the past that the cable ran along the bottom the chainstay. WIt it's current positon I can't mount the speed/cadence sensor for my Garmin 305. It is supposed to use the same spot as the brake cable. So, no cadence for my commute.