The car in question: 2000 Honda Civic, 27,000 miles.
The front brakes on this car has managed to wear down to the indicators, so we had a front brake job done at the local Honda dealer (OK, we can discuss the relative merits of that decision in another thread.). Fairly straightforward: they removed the rotors and resurfaced them, and installed new pads.
After the brake job, we heard noises that had not been there before:[ul][li]The noise is a pulsating rubbing/grinding sound that all observers agree seems to be coming from the right front wheel. The frequency of the pulsation is clearly in proportion to vehicle speed. The noise only occurs when the brakes are being applied, and stops immediately when they are released. I’ve never heard it at speeds above about 35 mph. When slowing down from a faster speed, that’s the speed at which it starts. It’s not always present, but it usually is.There is no perceptible pulsation felt through the brake pedal, or in the car’s motion - just the noise.[/ul]We took the vehicle back and left it for them to examine (overnight service). The word they gave us was that they “spray-lubed the CV joint boot.” No charge. The guy at the counter couldn’t even tell me if it was the inner or outer boot, and the dudes who actually did the work had gone home. This, frankly, didn’t make a lot of sense to me, but the noise did seem to be gone.[/li]
For about a day.
Knowing enough about this sort of thing to be dangerous, I jacked up the front of the car and popped both wheels off to see what I could find, if anything. I couldn’t see any signs of strange rubbing or wear on the disc, or anywhere in the whole assembly. I pulled the pads out and looked at them: they seemed fine. Nothing looked obviously wrong.
Except: disc runout seemed, to my untrained eye, excessive. I don’t have a dial indicator, so I can’t measure it. However, the (floating) caliper travels quite a bit laterally on each rotation of the disc. I observed this by starting the engine and letting it idle in Drive (with both front wheels off the ground). Actually, this is the case on both sides, but the right (noisy) side is worse. If I use the machined outer surface of the disc as a mirror while it spins, the image moves perceptibly as the disc rotates: clearly, the surface of the disc is not precisely perpendicular to the axis of rotation.
The only basis I have for comparison is my own truck, which also has floating calipers. There is no perceptible wobble in the caliper as I spin the disc. The “mirror check” also reveals no perceptible motion in the image.
I want to be able to speak intelligently with the dealer when I take it back there. Does the noise I describe sound like something that might be caused by a excessive runout in the disc? Does the amount of runout I vaguely describe sound excessive in the first place? Am I barking up the wrong tree?
Any suggestions from the gearheads would be much appreciated.