“... a sticking caliper can cause an intermitted drag feeling after you apply the brakes, but it won’t just start when you are driving and then stop.”
And that’s exactly what happened today, unfortunately. Driving on a country road back home at 45 mph and the drag/rub lasted about 2 to 3 seconds.
Thank you so much for your advice.
That sounds like what a close to failing bearing does. If you are driving along at 45 the brake calipers are not touching the disks. If there is enough friction for you to feel it that means something is not rotating close to properly. In theory it could be some junk touching the tire, or in between the caliper housing and the brake disk, or even between the car and the road but each of those cases except for the junk in between the caliper housing and the brake disk makes a lot of noise when it happens and basically requires you to run over something.
A failing bearing suddenly increases its friction because bits of worn metal are in the grease between the rollers in the bearing and they temporarily stop a part of the bearing from working properly. When that happens the bearing gets hot, and has more damage.
At some point the damage is enough that the bearing stops turning, or generates enough friction that it is like one wheel having the brakes on. At that point you are not going much further, and then you are waiting for a tow truck.