I've hadthis problem for over a year. When it's raining outside, and my explorer is in the garage (or parked outside) my brakes will grab. This only happens until it's driven for a little while. I have replaced the front pads and changed all of the brake fluid, & it hasn't helped. It seems like the front brakes are what grab and cause a sudden stop. I don't understand it. This happens during first brake applications even after it's been in the garage. What could cause it? Brake booster? Rear shoes have plenty of material left.