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While driving on a rough road, a bushing fell off from the front driver side suspension arm. I could not feel anything different on the 1km drive home. So I'm wondering what is the use for the part?

Random speculation from me, would be that it is protecting the suspension arm and the tire from damaging each other going over heavy (speed) bumps - possibly while turning. Would this be correct?

Mazda 6, 2009 2.0, Stc, Diesel, 140HP

The part and where it came from The passenger side where the part is intact

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  • 1
    possibly a sway bar link that has rusted off.
    – Moab
    Aug 7 '19 at 18:35
  • @Moab That's a good suggestion, but I'm not entirely sure. I tried search for pictures and videos showing the upper control/supension arm, only thing I could find in my 15 minutes searching is this - it is a used car, so might have the same issue, but it does not have anything attached to it as well. Any ideas? :) Aug 7 '19 at 18:49
  • Year make and model of vehicle?
    – Moab
    Aug 7 '19 at 19:57
  • Year, make, and model of vehicle plus some quick googling should yield an exploded parts diagram of the suspension, which will tell you exactly what the part is.
    – dwizum
    Aug 7 '19 at 19:57
  • Sorry about that. I've added it, but it's a Mazda 6, 2009 2.0 DE. I've found realmazdaparts.com/auto-parts/2009/mazda/6/s-trim/… but the upper control arm doesn't look like mine on my car. I couldn't find anything for my diesel variant. Aug 7 '19 at 20:08
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While it does look like a bump stop, I can’t see anything that it can bump against.

According to this page, part number 34-970A is a ‘dynamic damper’. Presumably it is some kind of harmonic damper to remove resonant vibrations from the suspension components.

Is it a lump of metal mounted on rubber?

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  • I've added two pictures of the item in question. But yes, it is a lump of metal that is hollow (lack of better word). Thanks for the answer! Aug 7 '19 at 21:32
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    I think you nailed it, I have never seen one on an upper control arm, but it is a diesel with a lot of harmonics. @HandyHowie
    – Moab
    Aug 7 '19 at 22:48
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    100% harmonic dampener Aug 8 '19 at 2:18
  • @HandyHowie How urgent is it to replace? None of the autoparts stores here have it (the whole unit) in stock, and the mechanic wants an extreme amount for the whole assembly. Aug 8 '19 at 15:58
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    I would presume that when the car was being developed that certain road speeds or surfaces caused a resonant vibration (noise or hum) on the suspension, so they added the damper to quieten it. I can’t imagine it would cause any other symptoms, so there is no rush to replace it.
    – HandyHowie
    Aug 8 '19 at 16:24
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It is possibly a rubber bump stop. It purpose it to stop suspension movement before things get to a point of metal to metal contact or the shock bottoms out. If the piece just rusted off you wouldn't realize it until the suspension bottomed out. It is possible that the rough riding you did compressed the suspension to the point the bump stop hit and was knocked off. If that is the case then you may have worn shocks or springs that allowed the suspension to bottom out earlier than it should have.

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  • When I rode on the pavement I'm not sure I was bottoming it out, but it was rough with lots and lots of smaller potholes about 1-3cm in depth. But it could be a possibility as the last pothole is a bit tricky one. Seems to be this. Thanks! :) Aug 7 '19 at 20:32

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