NC Rear Suspension Banging - what to check next?

Hi All,

First post here so hope I get everything right, apologies in advance if not.

  1. My model of MX-5 is: 2011 NC (MK3.5?)
  2. I’m based near: Bath
  3. I’m looking for technical help or recommendations on: Rear Suspension

I’m after some advice on what to check next on the (all standard) rear suspension, which is making a banging noise on both sides whenever I run over a bump. I’ve replaced the drop links and ARB bushings but am still getting the banging noise. Oddly it seems to get worse when warmer - either when the ambient temperature is higher, or when the vehicle has been driven for >15 minutes or so. That makes me think maybe it’s a perished rubber bushing somewhere which softens in warmer conditions.

I’ve pushed the rear quarters down and to my inexpert eye I would say the shocks and springs seem to be doing their job - there is reasonable resistance on the way down and it doesn’t bounce straight back up, but other than that I wouldn’t know how to assess them really.

I don’t think I have the skills to remove the shocks from the car, so I am wondering if there are any other checks that an enthusiastic amateur can make, or if I should just give up and send it to a professional?

Thanks for any advice - I’m hoping there might be a couple of simple things I can take a look at without having to start taking the suspension apart, because if I’m honest I have much greater confidence in my ability than my wife does, and she has an annoying habit of being right. And it’s her car :slight_smile:

Which model have you got?

I’ll make a guess first, it’s the Bilstein shocks if you have them?

It’s the 1.8 NC - embarrassed to say I have no idea what make the shocks are but everything on the car seems to be completely standard if that’s any help?

Not Bilsteins shocks then.

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The Bilsteins used to rattle on my car, just going over uneven roads, hit a pothole or go over a speed hump and it was ok, silent.
I swapped them for coilovers, a bit drastic I know but it was going to happen anyways, no more rattles. Others have commented about having the same rattles/noises coming from the Bilsteins, similar remedy change them out.
Now the you will have just bog standard suspension on the 1.8 but I think I’ve read they have collars that can rattle up on the shock. Someone else can confirm this as I’ve never owned an NC with the standard suspension so could be incorrect about the that.

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Ah, excellent thanks - I’ll be interested to learn more about these collars. I would actually consider fitting coilovers, especially if I had to shell out a couple of hundred already just on new shocks, but I should soon be the owner of an NB “project” that I want to put all the boys toys on. My wife doesn’t really drive the NC hard enough to justify the extra cost.

I have a nc2 2.0l kuro prht
When 1st test drove it heard a knocking from the N/S/R

But i just put it down to droplinks
Or such
So replaced both of these and while i was there t i done the antiroll bar D bushes

But the Noise still there
Was more noticeable when had a passenger in the car
I Checked it out and i couldnt find snything if car was on 2 poster ramp weight of suspension hanging or 4 poster with weight on the wheels
Done a bit if research and came across a post about broken coil spring
So assumed this
Eventuall sourced a set so could replace
I refurbed these so be case of one set on set off plus both struts would have done same mileage
So fitted thrm

Noise was away
Weyhey

So stripped both old struts down
To compare parts and check the spring heights etc
One from the side was knocking had bumpstop broken hence my noise

HINDSIGHT is a wonderful thing???

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Oooh, I can feel the frustration there! By the sounds of it a bumpstop shouldn’t be too tricky to replace, but I am struggling to find a decent guide onNC suspension parts and how to replace them - does anyone know a guide or video that shows things like the bumpstops, top mounts etc, and how to get to and replace them? All I can ever find is videos on how to fit coilovers.

I done a search on google found a american video on one
https://www.google.com/url?sa=t&source=web&rct=j&url=https://m.youtube.com/watch%3Fapp%3Ddesktop%26v%3DeCs1qakkWhg&ved=2ahUKEwi007_yvvLxAhXZi1wKHZLOBngQo7QBegQIBxAB&usg=AOvVaw3GEWX-Nk1vXEuED2n9_rPM

gave u the idea but is quite simple 2 nuts from inside the boot and a bolt from the underside at the strut itself bottom bit can be tight to get off but if hsve a jsck on the bottom can use this to adjust the weight on it then know it off with hsmmer and a bit if wood blunt chisel or similar
Can work tbe shocker ou if 2 of you but if remove the toe control link but mind watch for the metal tapered bush falling out

Stripping the shock easy but need spring compressors to remove
coil from the strut safely

https://ncmiata-servicemanual.com/books/g5w02/html/id021400802600.html
https://ncmiata-servicemanual.com/books/g5w02/html/id021400802600.html
https://ncmiata-servicemanual.com/


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Ah you star, thank you! Think I’ll make it a 2 man job to be on the safe side, otherwise there’s a risk that I end up with a load of bits pinging off all over the place and a wife moaning that she can’t get to work :smiley:

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2 sets of hand always helps
When stripping spring off would mark the spring at shock top mount with a paint marler tipex or something
Tops got to be fitted correct way so everything aligns up at the bottom
Good luck

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