NC Spring Failure

  1. My model of MX-5 is: 7002-NC, 70,000 miles
  2. I’m based near: Sheffield
  3. I’m looking for technical help or recommendations on: Springs

What causes springs to fail? Last year my nearside front broke, at this year’s MOT, both front and rear off-side are broken. I don’t drive over many speed humps or cushions, and have only done about 2000 miles in the past year. All suspension is stock, nothing altered.

Is it worth changing the other corner now as a preventive measure?

To be safe, I’d change all 4 and as it’s done 70k, shocks as well

Did it myself last year, expensive but worth it - used a Bilstein kit with -30mm Eibach springs about £690

Could just be a rogue. Japanese springs are normally far better quality than Fords and Vauxhalls for example which corrode and snap regularly. As above change both sides.

Once again it’s the appalling state of our pot holed third world standard roads. What is even more annoying is the fact that despite the fact the Government regularly says it is giving money to Councils to repair them nothing happens.

Broken coil springs seem to be a fact of motoring life these days. Usually starts with surface corrosion which produces pitting which acts as a stress raiser from which the fracture develops. The state of the roads certainly doesn’t help. I changed one on the back of a friend’s VW recently. We examined the fracture face and it looked looked like it was a classic brittle fracture. We replaced both rear springs while we were at it.
JS

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If you don’t mind me asking, which Bilstein shocks did you go for? B6 or B8? I read somewhere about NCs riding a bit higher with the non-Mazda spec Bilsteins fitted, but I’m hoping that could be down to twisted bush syndrome! The rear shocks on my car are leaking slightly, so I’ve got a full set of Bilstein B6s on order from Demon Tweeks.

Or if you fancy a cheaper fix than brand new im selling these on eBay.

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I’m on a complete 2nd set of springs on the Mk1, to be fair the second being an optional matter during a refurb. 27 years old ( not me unfortunately) and circa 146k miles.
I’ve always replaced full sets, as they are cheap, on the advice of “My Man”.
On our second set of Mk2.5 springs as well, done at I think 93k miles when the front 2 cracked up near the turret tops. Thought it best to ditch the rears anyhow due to age. The shocks, surprising, are all still sufficiently tight and leak free and in any case it’s an urban Driving Ms Daisy mostly in the hands of The Boss Lady. Nor did I fancy a tight front end which in theory could induce understeer in the wet, to a “seasoned” softer rear set. And yes…it’s lasered bang on.
Bottom line they are nothing other than twisted steel wire and I guess age related metal fatigue plus as said the appalling UK roads don’t help. Polos & Golfs are a brilliant source of repeat business according to our garage…seems we are not alone.
Edit:
Actually just remembered Mk1 rears as well were renewed 8 years back…cracked.
I guess going a bit ballistic through some of the rougher sheep track roads up here helped…not.

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I believe the shocks that come with the B12 kit are the B8 which are slightly shortened
https://www.bilsteinsuspensionstore.co.uk/bilstein-b12--prokit-suspension-kit-46190345_p31028782.htm

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At that kind of mileage if they are the original shocks then it’s probably not worth replacing the springs, potentially all the shocks would be at the end of their life.

If you want the best value shocks, MeisterR Zetacrd, they are £800 but they are very good quality. Height adjustable, spring load adjustment, adjustable dampers etc very plush suspension for the road in my experience with my Mk2. Reliable also, a guy used his his MK3 on Nordschleife/Nürburgring 300 laps, had the Meister suspension stripped down and it was in perfect working order. That’s around 3800 miles of pushing the car hard.

Cheaper option is 30mm springs on your standard shocks, Eibach springs are £150.

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I used the excuse, sorry reason, of broken springs to convince the wife that 30mm Eibach lowering springs were the way to go. Roddisons did tracking after. Had got 2 new shocks on and will
prob do the next 2 this year when allowed out to play