My 05 Jetta TDI is intermittently making a rubbing/grinding noise. Not in stop and go traffic but when I come to a stop at a stop sign, but only just before I come to a complete stop, not as soon as I hit the brakes. The shop that put the brakes on (about 18000 miles ago) looked at pads, rotors and pedal but said it’s all fine. Could it be the booster, abs, or something else completely?
Does it feel like the ABS is kicking in? There are various problems that can cause the ABS to engage at low speed when it shouldn’t. Most of those issues would have something to do with speed sensors.
This makes it a brake system issue, but not anything to do with pads/rotors. Was the shop able to reproduce the problem?
Maybe the problem is not related to the brakes at all and is actually something else.
An exhaust heat shield rattle can often come across as a grinding noise and a suspension fault can also make an odd noise depending on what part of the suspension is involved.
Generally speaking, with suspension it’s the sway bar bushings which are rubber and harden with age. At some point the hard rubber may start making noise, especially with the onset of cooler weather.
Both of the above problems can vary and come and go based on the stance of the car.
You might try bouncing each front corner of the car very briskly up and down while listening carefully for any noises. That may reveal a suspension fault.
With the heat shield this often takes a few whacks on the exhaust with a rubber mallet or protected fist while also listening carefully for any buzzes or rattles.