Horrible metallic noise at the rear

[Kerrath]

Long story short, I've replaced that axle and rotor. I got to drive it for about a week before the slave cylinder died and I had too much stuff come up to get to replacing that til about two weeks ago, then my wisdom teeth out, and so, today is the first day I've had a chance to drive it.

I discovered the noise was back, despite the part replacements, so I removed the brake cable, even though I doubted it was the problem, and sure enough, the rattling continues.

Some more info I've determined through extensive listening is that it only seems to happen 15+ miles per hour and only after some driving, as if it needs to be warmed up. Prior to becoming a near consistent noise, it seems to happen only on bumps or rough patches in the road. Every once in a while it cuts out, but usually for less than a second, then right away starts again. I've had it up to about 60 while being able to listen and speed doesn't seem to make it go away. It's shriller than I previously would've previously realized.

Some thoughts that have come to my mind are these:
Wheel bearing (though I doubt it's likely)
Something caught in the rotor ("" "")
Loose caliper pistons causing intermittent scrapes against rotor
The dust plate flexing enough to bump the rotor
Something in the ABS sensor ring (just replaced CV axle, so unlikely)

I am reasonably certain it's specific to the driver's side wheel area, though it's hard to tell from my seat, using only echoes. It's possible it's coming more from the differential or far rear driveshaft area. Nobody I've asked to listen from outside the car has been able to tell either.

I've jacked the car up to spin the wheels but no matter what speed, it doesn't manifest the noise. Whatever is wrong, I need/want to replace it and I am so far unable to solve the issue.
Need your help please.

[Leaf]

E-brake shoe's fuck up alot on these car's. Make sure your's isn't in pieces inside the hub... like mine.

[Kerrath]

E-brake shoe's fuck up alot on these car's. Make sure your's isn't in pieces inside the hub... like mine.

I've entirely removed the ebrake system from that wheel. No cable, shoes, springs, nada. Sorry I forgot to mention that.

[Kerrath]

What are the odds it's the metal tabs on the CV axles? The passenger side one I didn't do and the PO could've installed it without loc-tighting it. Seems like a longshot because I think I would've noticed that.

[Kerrath]

Took a look a bit ago and I can't find any loose tabs or bolts on the axles. Not able to spin it right now since it's on the ground, but don't think that's the problem.

[Kerrath]

Are there any bearings in the rear end where the race that is supposed to be fixed in place could've broken free and is spinning instead, and catching every once in a while? It seems like it'd improve once it got warm, which is not the case, but it's something to look into.

[Kerrath]

Help please?

[Kerrath]

I recorded the sound, but unfortunately lots of wind too, so please bear with me. For some reason only the video mode captures the noise at all. You can hear it best at the beginning and in the last 3 seconds, but if you listen carefully, it's constantly there.



I kicked and shook lots of stuff and I couldn't get anything to reproduce the noise or anything similar. Then I noticed that my rear right rotor is warped and I thought that might be the cause, but when I brake, the noise doesn't stop or really seem to change.

If any of you are audio gurus, the sound seems to be between 2khz and 4khz but with my rudimentary software, I can't isolate it but maybe you can.

Still would appreciate help with this, and thank you everyone who's offered advice so far.

[Kerrath]

Is anyone able to hear the noise?

[bmwpower]

All I hear is the wind....

[Kerrath]

Alright, well, I'll work on it again later. The sound is definitely there. At the beginning you can hear it start up it kinda and you can hear it more clearly in the last 3 seconds when I put on the right side of the car with a handy angle.

[Kerrath]

I'm pretty sure the noise is brake heat related now. It's good on the freeway but after the long brake for slowing down, the noise tends to appear. A while on surface will make it start and a long drive on the freeway will make it go away.

I'm thinking it could be a damaged/improperly installed rattle clip or warped rotor or something. What do you think?

[Kerrath]

I replaced both my rotors with brand new ones and replaced rattle clips today and my noise is still present. I also removed the rear right e-brake cable since I never use it and it seemed that it was constantly dragging which could've explained why that rotor got warped to begin with.

I noticed that my CV axle on that side doesn't stay completely centered while spinning. It was hard to notice, but I was being highly critical. Could that make the described noise?

[MIKe30]

i heard it. It sounded like a whizzing/whirring noise. Check the front and back of your brakes/rotors/pads. if it's none of them i'd guess wheel bearing (although when mine went out on me one time it was a loud howling sound that increased with speed).

[Kerrath]

When you say check the front/back of the rotors/pads, what do you mean exactly? What should I be looking for? I was running it on jacks with wheels off to see if I could get any noises or sounds to develop and I can hear that both the brakes brush lightly at times as the rotors aren't absolutely perfect. Other than that, I can't find anything else that explains the sound.

I've done the wheel bearing test where you're supposed to attempt to wobble the wheel. Mine don't exhibit any symptoms undergoing that test, so I wonder, how effective of a test is that? I've already thrown 50 bucks at the rotors as a hunch (one needed replacing anyway) but I dont want to throw a crapton of money at replacing a wheel bearing if it's not the problem.