2008 Impreza 2.5i Intermitent Grinding Rotational Noise

I’ve got about 88k miles on my 2008 Impreza 2.5i manual. The last 30k miles on it have been rather rough (~60 miles a day stop-and-go highway traffic). Somewhere around 80k I developed a leak in my clutch hydrolic line that lead to a clutch replacement around 82k miles (I had a few leaks simultaneously so diagnosis of the clutch line took longer than optimum). I also had new break pads installed around the same time, tires rebalanced, alignment, and one new ball joint on the front driver-side wheel. Anyways, after this work I had a noise develop that I’ve had checked out twice and has yet to be diagnosed, so I’m turning to the larger community for suggestions.

I am getting a grinding noise that occurs with both front breaks but at different, specific, reproducible points in the tire/rotor/etc rotation. It also only occurs with mild break pressure (most noticeable during a gradual, easy deceleration). The frequency changes with speed, so I know it is rotation point specific. Heavy break pressure does not generate the noise. The noise is also the most noticeable after the car has been at rest for a number of hours, and lessens the longer I’ve been driving continuously (but never goes away completely). I have not noticed much change as a result of moisture, and I live in Colorado so our humidity is at a minimum. I’ve also had my rotors checked to make sure they aren’t warped, and I’ve been assured that my break system looks good and clean.

Thanks for any help! I’ll answer any questions as best I can!

Bump

If you had the brakes checked by the people that did the work, it is not a miracle they did not find a problem. They may not really want to find the problem.
I’d lift the front of the car up and rotate the tires manually so see if you can hear anything and narrow it down to left or right.

Planning on doing that this weekend.

As for the break work, the two garages I’ve had look at this are not the ones that did the original break work (minus the ball-joint replacement, which I had done at one of the two).

You might also check to see if the brake calipers are stuck.