This started on Saturday rather quietly; I noticed a slight grinding noise, I guessed there was dirt or a stone between the pad and rotor. I noticed some (slight?) grinding in the rotor when I stopped 50+ miles later (I wasn't going to just turn around that day, it also didn't seem to be a big problem) and now it's over a hundred miles later. The car barely moves now (the rotor does not look much worse though, see the pic) and the car is parked safely in the driveway after being towed home. Someone heard the grinding at a grocery store, I said "It sounds like hell, doesn't it?" and he said he flipped an Explorer after having that same grinding noise. I thought I would not mess about. I can change pads, rotors, calipers and bearings but I haven't done it much. What might the problem be and how might I diagnose it? I thought maybe I can or maybe I can't temporarily take the pads and caliper off to tell if it's the caliper or the wheel bearing that's causing this horrible friction. Then again, I don't know if that would be a bad idea or if it's standard practice. I'd suspend the caliper if this is how to diagnose the issue. I am not sure if I may need to change the caliper, pads, rotor and wheel hub. Hopefully it won't cost too much. Picture of the outer side of the rotor included.
If there's no damage to the rotor, then it can only be one thing: the park brake set inside the hub. If I had to guess, one of the parts broke, and is now jamming the hub.
The front face of that rotor you show looks fine. When a caliper hangs up, which I suspect, it's the inner side that almost always takes the brunt of the damage. Is that brake heating up? The smell of burning brakes is pretty noticeable. STH above makes a good point about the park brake mechanism, especially for rust belt cars. None of this will make your car flip over
Thanks for the suggestions, right now it seems like it was the wheel bearing(s) though. When I took the rotor off a few hours ago, bearing pieces fell out immediately. It was difficult just driving the car in the garage. I found that by this issue, it also made the rotor and whole wheel go off kilter; that is, I may or may not need an alignment after this.
Alignment on the rear? If that's the case, it would be because axle attachment hardware's FUBAR. So inspect everything on both sides carefully. But usually, those bearings fail just because you're at the end of its service life, or because the nut on the stubshaft was incorrectly torqued- left too loose or too many ugga duggas.
Should be a press in bearing. Not the worst thing in the world, but I usually pull the whole knuckle off the car to do those. Much easier working on it mounted in a vise on a bench than on the car.
Ouch. That rust. Reminds me of what Dad told me about the '56 Country Sedan wagon we had in Pennsylvania, before he went to Vietnam, and the rest of us moved to Portland, OR. The tabs were coming due, like three months before Dad was to ship out, and it had to be inspected. Well, it had too many little rust holes in the body (for which Dad thought that it wasn't 'bad' bad), so the state inspectors would not pass it. So he ended up giving it to the son of the farmers we lived next to, for him to use at high school for his ag/mech classes. But I'm willing to bet the kid fixed those holes, and turned it into a shaggin' wagon!