Excessive brake dust

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ghost

ghost

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Yesterday, I noticed that my rear passenger wheel had brake dust all over the rim, not on any other wheel.

I only use my brakes to hold after the high regen brings me to a complete stop.

I assume this is from traction control, but I've never seen this before. I think I might need to turn traction control off, if it continues to happen.

Anyone have any other insight?
PXL_20220610_001204614.MP.webp
 
ghost said:
Yesterday, I noticed that my rear passenger wheel had brake dust all over the rim, not on any other wheel.

I only use my brakes to hold after the high regen brings me to a complete stop.

I assume this is from traction control, but I've never seen this before. I think I might need to turn traction control off, if it continues to happen.

Anyone have any other insight?
View attachment 16786
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Option 1:
Because it's only on one wheel, most likely the parking brake was dragging a bit. If you roll down the windows and drive slow you should be able to hear if it's still dragging.

Option 2:
Because it's the rear wheel, it wouldn't be traction control but could be stability control. Were you having a bit too much fun down a curvy road?
Not sure why this would be only one wheel though, unless you did a dozen laps on a roundabout lol. Maybe it happened to get wet or something so the dust stuck better?

Option 3:
If you charged to 100% (or were driving very aggressively and the drivetrain was too hot), the car will use the friction brakes to slow you down even if you don't touch the brake pedal. Again, not sure why just one wheel other than possibly getting wet
 
Just checked again, and it looks like there's brake dust on the other rear wheel. Not sure why I didn't see it yesterday. I think you're right about #3: I was fully charged so probably was using the friction brakes.

Thanks!
 
Puppethead said:
Look on the bright side, the traction control uses the friction brakes just enough that we don’t have to worry about brakes getting frozen from non-use.
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The brake rotors on our Clarity Plug-In Hybrid are a rusty mess from disuse--they work, but they sound terrible. However, it's not only because we use regen braking as much as possible, it's also because both my wife and I always choose to drive the SE while the poor Clarity gets ignored.
 
I noticed a fine coating of brake dust over the entire hatch within the first couple of days after taking delivery. It was very obviously brake dust; I don’t live in coal country or Victorian London.
 
SameGuy said:
I noticed a fine coating of brake dust over the entire hatch within the first couple of days after taking delivery.
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That might also be road dirt. The hatch design of the Hardtop is one of those that causes an upward airflow from underneath the car. The back is always the dirtiest part of the car.
 
Reeeally seemed like brake dust to me. The Subaru has a similar low-pressure area below the wing and road dirt around here is brown, not black.
 
SameGuy said:
Reeeally seemed like brake dust to me. The Subaru has a similar low-pressure area below the wing and road dirt around here is brown, not black.
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Brake dust is also brown-ish not black (see first post's picture) so it's some other mysterious substance coating your car
 
Interesting, we've noticed the same, but only on the rear. There is also a subtle intermittent rubbing noise (boarder line metallic) originating from the rear, primary during turns, but this intermittency occurs primarily during warmer days, nonexistent with mild conditions below 80F.

I've suspected brake rubbing, but efficiency remains fantastic.

We've tested this going down a steep hill at slow speeds, using regen and no brake pedal applications, we then accomplished a physical temperature check of all 4 rotors. The front two were cool, the rear two were unpleasantly warm to the touch. Driving was incredible mild, so we can rule out aggressive applications, there was also plenty of battery buffer for max regen.

This is such an intermittent issue we've decided to live with it, but will bring it up whenever it's in for service. The brake dust is mildly annoying on the rear, but manageable for us.


Sent from my ONEPLUS A6003 using Tapatalk
 
Zim said:
Interesting, we've noticed the same, but only on the rear. There is also a subtle intermittent rubbing noise (boarder line metallic) originating from the rear, primary during turns, but this intermittency occurs primarily during warmer days, nonexistent with mild conditions below 80F.

I've suspected brake rubbing, but efficiency remains fantastic.
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I've noticed a similar rubbing on my car but rather than being subtle, it makes an annoying squeak during slow right hand turns (and only the right side). It will stop with any amount of brake application so definitely the rear pads rubbing ever so slightly on the disk.

There was a thread about this with some others experiencing the same thing but no solutions. I've found the same thing reported for ICE MINIs so also not related to regen, probably just the rear brake design. My guess is the parking brake retraction isn't far enough but I haven't figured out how to adjust it.
 
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