KO products are very reliable. I have been using the 2144 on my throttle/brake for over a year.....no problems.
Do you use fuel tubing or a spring on the end of the linkage that pulls the brake? THere is a point on the brake cam/plate/disc where movement of the linkage will come to a dead stop, that's when you will strain the servo; do it long enough and you'd nuke it.
BTW, by using fuel tubing you would have better modulation on your brakes.
Please check EPA on Tx too?