Suzuki Samurai II braking

Wave to all heart mechanics, my problem is as follows:
I have a Samurai II year 98, in which it has braking problems, when I make a normal braking the front wheel tends to stop (blocking) before the right which causes me to go to the left, I have tried by braking this stabilize it is stabilized but it still tends to stop the left before the right. It is appreciated that they can help me, how fact it has a dosing valve which is little to operation.