Intermittent vibration from rear at low speeds.

Hi guys

I have a 13 Prius two with 140k miles. I'm dealing with a weird intermittent problem that happens about 30-45 minutes of driving at low speeds. But not consistently at all.

I was driving in traffic on a smooth road today and suddenly I felt a vibration/noise, from the rear. It would increase or decrease depending on speed. I thought something was dragging so I pulled over to take a look under the car. Everything looked fine.

I started driving again and the sound and vibration was gone. And it didn't come back for 70 miles of driving after. This is the third time I've heard this and each time it was under 30 mph and went away. It happens for like 5 seconds then once I slow down to look at it, it's gone.

What do you guys think this could be? Could this be a wheel bearing? A stuck caliper guide pin? A stuck caliper? Brake actuator failing?

I do feel a very very subtle slight vibration when I'm driving but it's not violent or loud enough for me to be able to decipher if that's road noise/ bumps or if it's a wheel bearing.

I took my rear wheels off and honestly it didn't feel like a lot of play.


I replaced the rear brake pads about 10k miles ago and I am fairly certain I aligned the dimple on the caliper properly with the OEM pads I put in. I'm not sure how good the caliper grease that I used is, it's the CRC brand. I've also checked my tire pressure and all is good there.

Have any of you guys run into this before?

I'm at my wits end with this car. I drive Uber and I'm constantly needing to fix little stupid problems.