i had the same thing a while ago but i am not shure if it is the same !! when i first had my bike it had that brake and was fine but as i was progresing and getting better i had to keep changing my setup.but after a wile i realised that i was titening it one ride then after i had wrode a bit it i had to tighten it again.i found out that i had had either pulled it to hard and tightend it too mutch. in the end i had to replace the whole piston that is connected to the leaver.aprox £70 not cheep. send me a pm if u need to ask some pdesperate questions Andy