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      10-27-2010, 08:57 PM   #1
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Stopping coil slap noise

Hello All -

I'm passing along this advice/experience in the hopes that someone else may benefit from our discovery via long period of trial and error.

I had a recurring thunk/clunk coming from the left rear corner. It made a 'gronk' suspension noise that was rather loud and very annoying. Easily replicated in a quiet parking lot at 10-15mph by first loading and then unloading the left rear corner. Even a small bump would do it.

I suspected worn bushings in the Rogue RSMs; bought a new set and replaced them. Noise abated for around 50 miles then returned. Both Rogue and KW were very helpful and responsive on support questions but we could not find the cause. Plug for Rogue and KW support.

We eventually tracked the problem to the lowermost two coils of the KW spring rubbing together when loading/unloading that corner. The friction had worn through plastic factory outer sleeve (below), allowing the painted metal coils to bind/rub against one another, especially when that corner got unloaded, creating the noise. Despite being on the car only four months, the wear on the coils was visually obvious :

Attachment 448399

On a tip from KW we tried wrapping the lowest coil of that spring with a layer of electrical tape, which temporarily eliminated the noise and confirmed the source.

I finalized my fix with spiral-cut 'coil flex' cable minder, 3/8" size. Goes easily around the bottom-most coil or two and eliminates coil binding/noise. About $5.00 for ten feet at radio shack (link) or electronics /home supply store. Very easy to install/replace. The Coils cannot contact each other any more. 500+ miles so far of quiet driving

Attachment 448418

Last edited by blender; 11-21-2012 at 11:31 PM.
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      10-27-2010, 09:02 PM   #2
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Thanks for the info! Where did you buy it?
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      10-27-2010, 09:26 PM   #3
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I seen those in home depot / lowes, probably electronic / wiring stores.. like for cleaning up wires for home tv & etc..
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      10-28-2010, 06:56 AM   #4
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Good tip.
Alpinweiss '07 M Coupe •DKF Section1•RPi GT exhaust•Fabspeed Headers•VRS Hyper-Narrow rear wing•Autosolutions SSK•APR splitter•Tekarbon headlights•StrongStrut STB•KW Clubsport•H&R ARBs c/w Turner Adj Links•Poly FCAB/RTAB•Volk Racing G2•Direzza ZII•Stoptech BBK•Vibra-Tech mtr mounts•
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      10-28-2010, 08:29 AM   #5
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Will the springs chew through the coil wrap as it did the paint? How are they holding up so far?

///M Coupe: RPI Scoop, OE Strut, CDV, Volk RE30, SS Brake Lines, Stromung Exhaust
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      10-28-2010, 08:37 AM   #6
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love the reverse r&D on this forum....
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      10-28-2010, 09:31 AM   #7
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believe it or not, this comes stock on a lot of cars. i've especially seen it when changing the suspension on japanese cars. it is very common
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coil, noise, springs

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