I recently sent my truck to the local mechanic for an inspection, easier than going to dealer because he picks my truck up while at work. He calls and says I need new front pads and rotors. 40k miles, 2013 V8 FX4. I have been really busy at work and figured I'd just let him do it while it was already at his shop.

A couple days after getting the truck back, I get a brake light while heading up a long hill. Note, up and not down and I never touched the brakes. I fiddled with parking brake a bit thinking I might have bumped the sensor with my foot, check temperature of the rotors by feel, verified brake fluid. I never noticed a change in braking performance. Turn the truck back on and the brake light is off. I figure I would let it go for a bit to see if it happens again.

That was a couple weeks ago. Today, on my ride home from work, I was sitting at a red light with my foot on the brake and I felt the pedal go to the floor. Recognizing something was wrong, I make my way to the side of the road and it seems like a significant portion of my brakes are gone. The brake light then comes on. I limp into a parking lot in first gear, throw it in park, and open the hood. I am expecting I blew a line and the reservoir would be low. Surprise, it is full. I nose around all four wheels expecting to find a leak, nothing. Frustrated I contact the mechanic and he says he can't get me in to look at it until Wednesday (it is Friday). I put the truck back into Drive and confirm that I am still having the problem.

Based on the previous experience and not having any other options, I shut the truck off and turn it back on. Brake light is off. I put it into Drive and creep forward, everything seems fine. I drive around the parking lot, no problems. I then get my wife to come down to follow me home. I proceed home, stopping at multiple stop signs, stop lights, extended periods with foot on the brake, slow speed braking where I might expect a booster problem, lock up the ABS a couple times in my drive way, no problems. I contact my mechanic and he says he has never heard of anything like that. His recommendation is to let it go to see if it happens again because he feels like it is an electrical issue. I think that is crazy, because if I would have needed to stop earlier today, I would have piled my truck into the back of another car or worse.

I can't wrap my head around how an electrical issue would present a problem that felt like low fluid levels or air in the line. Perhaps part of the ABS system is failing? I unfortunately don't know much about the job he did, but he is a mechanic I've used for years and generally trust his work. I would appreciate any thoughts or comments.

Thanks!