So the current production brake-set on the Trek 7500 Hybrid is: Brakeset Shimano M422 w/modulator, Tektro levers, Kraton inserts, bell. From the Trek website. Hmm...

I replaced my brake-set on the Trek 7.5 FX I bought last year with Avid Single Digit 7 brakes. Solved a plethora of problems I was having with the stock brakes. On the brake-post where they are mounted on the seat-stays, one of them took the entire top of the post off with it. It had been cross-threaded on and took the whole thing as I was about to install the SD 7's. I took it, under warranty, to the LBS. They managed to find an identical post and put it back together.

I suggest taking it to your LBS and ask them about spare-parts, etc.