2009 Suzuki Wagon

We were driving down hill and at a speed of 35km/hr and then slowed down as there was a speed breaker, when I applied the brakes the pedal was to soft and the car braked but it skid a few mtr and then when I apllied the brakes agin it was fine, it was moderately wet. After a few km agin we encuntered a similar problem after a couple to drives I never observed this again. What could have caused this problem, I have checked for leaks couldnt find any. What do you recommend to carry out further analysis
October 12, 2011.

Suspect master cylinder piston seal fault

Oct 12, 2011.
Is the fluid level correct?
Is vehicle equipped with ABS?
With vehicle stopped, Start engine and depress and hold the brake pedal slightly. If the pedal starts to sink after a few seconds, the brake master cylinder is bad.

Oct 12, 2011.