Like Dennis said....check ur fluid level and check for leaks. I am on my third master cylinder and just added fluid last week due to it being low. You will also notice weak braking if fluid is low ----or if there is a vacuum leak to booster then the brakes will be really hard to step on........

My fluid loss was from one of the slave cylinders. <img src="/forums/images/graemlins/kewl.gif" alt="" />