first you must find the leak and fix it. there is probably a leaking wheel cylinder on one of the brakes. so you have 4 wheels check and see which one is leaking. you may be luckiny enough to see the wetness around one of the brake drums.
brakes are fairly importanr so if you are not mechanically inclined , maybe you should hire some that knows how to do it
it may be someone else;s life that you may save if not your own
ron