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Worn rear spring isolator - questions

Hey guys,

I have been trying to track down some annoying squeaking from the rear end of my car and today pulled the KW V3 rear springs out and the rubber isolator at the top was worn through on both sides, resulting in the spring directly contacting the chassis. Each isolator has 2 different part numbers printed one on top of the other: "CR33-5599-BA WHITE" and "C757B 9R33-5599-AA". However, when I look at an online parts fiche, the part number is listed as "5R3Z-5586-AA".

So my questions are:

1) is the 5R3Z number an updated part number?

2) how can I prevent this from happening again? Car only has 10.5k miles on it.

Any help would be greatly appreciated! Thank you.



  • Boss isolator.jpg
    Boss isolator.jpg
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I was replacing my springs and noticed the same thing as you. Replaced with PN 5R3Z 5586 AA. I have 100k on my Boss and only the drivers side was worn through. I also replaced the lower insulator.
Very interesting. I ended up replacing mine and I added the same insulator down on the KWs adjustable spring perch in an attempt to stop the squeaking. Didn't help so the source still is unknown . . .

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