Replaced pads and rotors and now have noise

[dadsbmw]

I replaced the pads and rotors all around several weeks back. Since then the car has constantly been making brake noise... mainly from the front passenger wheel and both the rears.

The front has been making a scrubbing noise as well as a nice little squeek when cruising with no brakes and when theyre applied. I took it all apart and reinstalled with no change. This weekend I finally just went out and bought ceramic pads, hoping that the cheap semi-metallics I bought were the culprit. I also re-greased the guide pins and they came with new dust boots and mounting bolts. First drive revealed that the noises were gone! On my way to work this morning however, I discovered that all the old noises were back, just to a lesser extent.

Any ideas what may be causing this or how I can fix it? Its definitely not the dust shield rubbing on the rotor. Is it maybe the rotors themselves that suck? From what I can tell the drivers side doesn't make any noises.

The rear brakes having been making more of a GRINDING noise, which Im also going to replace with ceramic pads and replace the ebrake shoes and hardware to see if that will do the trick.

[ELVA164]

Pad choice is up to you, just realize most ceramic pads will hurt cold braking torque. I'd go with stock ATE pads. If the pads are dragging though--which is what it sounds like you're describing--it suggests the calipers are sticking and need at least a cleaning and probably a rebuild. If it's a slight rub, it's not really an issue. If it's a loud rub/squeak or grinding like you describe, need to take a look.

By the way, did you try spinning the rotor by hand to investigate the source of the noise and/or determine how much the pads are dragging?

[dadsbmw]

Im not too worried about temperatures as this is purely a daily driver. As such Im just trying to go with whatever's cheap but works. Its really more of a slight rub, but I can hear it with the radio turned down from inside the car.

I did spin the rotor when I had if up after I replaced the pads and there was a very minimal amount of rubbing on the pads, but this was after I had fully depressed the caliper piston.

So where would it be sticking? Is it more likely that its the piston sticking and continuing to apply slight pressure on the pads after I let off the brake, or that the caliper guide pins are sticking and not letting the caliper back out? The calipers, if original, do have 380,000 miles on them... perhaps its time for a rebuild!

[ELVA164]

Because it's a daily driver, you'd want to have pads that work well from cold. I speak from experience; I installed a set of "sporty" pads when I first did my brakes, but not only did they fail to work well during regular road use, they actually glazed and warped my rotors. I'm not saying your pads will do that, I'm just saying the OEM pads work really well for regular driving and I won't be deviating from them again.

Calipers usually stick at the piston, due to corrosion around or on the piston. The guide pins could be a source, but more likely than that is the surface of the caliper each end of the piston slides on. I always wire brush/scrape these when I remove the pads. 380,000 miles is well, well past any service interval so I'm sure they aren't original, but with that many miles I'd consider them at least suspect.

[dadsbmw]

Thanks for the help. I'll do a caliper rebuild and report back.