Ford Repair: ABS Brake Issue, brake fluid reservoir, ford explorer sport

Question
Good evening and I hope this e-mail finds you well. I am the proud owner of a 1993 Ford Explorer Sport model that has 147,000 original miles on it. I have owned this car since it rolled off the showroom floor and it has been good to me over the years. Recently, I had the front brakes changed. The pads were changed along with the resurfacing of the rotor. Since that time, I have noticed that I am experiencing intermittent times when I press on the brake pedal and it is VERY TIGHT as if it will not go down to the floor and I feel VIBRATIONS and RUMBLINGS when my foot is depressing the pedal. Like I said, it is intermittent and I have noticed that it happens generally in the AM after the car has sat for the night, but goes away and the braking system returns to normal operation. I have taken it to my mechanic, but like going to the dentist, the problem never surfaces. I am wondering if this is something you have heard of or experienced? I will say that I have looked in the brake fluid reservoir and the fluid is NOT clear which concerns me. I'd be interested in seeing what you think. Thanks!

Answer
flush fluid which is a regular maintenance item-sounds like bad abs sensor or wiring-could be slack in wheel bearing also-do you hear any slight roaring when turning from rt to left while driving-slack in wheel bearing could cause this-metal shavings or trash so to speak on the wheel speed sensor could cause this also.