Our car has only about 22k miles on it, but it's always been kept outside (in NY) and went for several months this winter with no use. This summer, we developed a low grinding sound when braking. A visual inspection shows there's still a lot of brake pad left, but the rotors are seriously scored with grooves and rather rough to the touch. The rear ones are worse than the front and the sound seems to be coming from those. My question: should I just live with them as they are until the rough rotors wear the pads down and then replace everything, or should replace the pads early and get the rotors ground?
If the pits are really deep, then grinding may not be an option - there is normally a minimum thickness specified.
I would suggest that you save up for the new pads and rotors and change them when ready. That is ONLY if the existing ones are stopping the vehicle as they should - a bit of extra noise is not an issue as long as the stopping power is there.
So this question has been viewed a lot and I wanted to post a followup: I ended up replacing the pads all around, and the rotors on the left side of the car that were really pitted (rotors on the right side were totally smooth) - this was at about 24K miles. Just now, at 45K miles, I got a break pad warning light on the car. Since I had to take it in for regular service, I asked them to check it out since it looked to me like all of the pads still had wear on them, but I was noticing the same sort of un-even scoring ont he rotors that I'd seen before.
The dealer said the pads were worn down on the hard-to-see (and hard to feel) inner side of the rotors and the rotors were once again worn very unevenly to the point that they should be replaced. I told them to go ahead, since I didn't have the time to do the job again. This seems super-excessive to me, and really weird - I've never seen this before in my 30 or so years of car ownership and DIY mechanic-ing. Then again, there are times of the year where this car goes for days to weeks at a time without being driven. This last time was the first time I have ever had someone other than myself do the brake maintenance on a car - since it's such a simple job.
Note that the car is a 2014 BMW X3, and has otherwise been fine.
...very weird. I will probably be trading in the car in the next 12 months and I'm looking forward to not having to worry about it.