Rust on rear suspension

  1. My model of MX-5 is: __NC Kuro edition
  2. I’m based near: __Hampshire
  3. I’m looking for technical help or recommendations on: __Advice on rust

Hi Everyone,

Finally got my first MX-5, bought it couple of weeks ago without test drive (I know…), car’s only done 35k, body and interior is in a very nice condition, drives really well. My only issue is rust, specially on rear suspension. I’m in talk with the dealer, don’t want to name it, but would appreciate some advice. Car got MOT-d before the sale, not even an advisory on it. Few days after I got it home, I had it lifted to check the undercarriage. For me the rear suspension looks very corroded, not much on the body itself, but more suspension arms, etc. Dealer says that they are happy to have it back and get it cleaned by the guys who did the MOT, and it’s pressed metal, so won’t rust through, it’s all surface rust, so I thought I ask the people who know more about it than I do. I have made a video, can’t upload it here, so it’s on WeTransfer, could I ask you guys to have a look at it and put my mind at ease or give me some ammunition to get back to the dealer if you think it’s not something you just clean up. Link:

I think this is pretty typical of the NC components, they do all rust like this.
Mines on 51k 2007 model and its much the same.

I took mine to a bodywork shop to quote me for undersealing (you should considering it) and he said all of it is solid and will just be surface rust.

I think it’s worth having the shop clean it, then if its worse than they originally thought they will be obligated to fix it.
The rust was there when you bought the car so they should get it sorted for free.
Personally I think it looks worse than it is but I only have the experience of my own NC.
I wouldn’t worry about it too much.

If you do go for an underseal, most of us will recommend it then all this kind of stuff will be cleaned with a flapwheel/wire brush and the body shop can paint it to prevent the problem returning in the near future.

As above, generally they suffer from surface rust on the suspension and subframes (there are other areas obviously) the trick here is to ensure any surface flaky, powdery rust is removed, a rust converter applied to all those areas, and then a protective layer
(underseal, stone chip, paint or whatever) very common issue TBH and should not detract from your enjoyment of the car. Nice if you could be there when car is up on ramps to get a good feel for what’s going on. :+1:


Mine, an ‘06 mk3, was similar. Plenty of time with a wire brush, grinder, kurust and your choice of protective treatment and it can be brought back to a nice condition, but best to do something, don’t leave it…

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That looks pretty good for a Japanese car nearing the end of its design life tbh, I’ve seen far worse on cars 4 or 5 years younger, particularly those used in Scotland and the North of England.
I’m pleased for you that the dealer is prepared to do something as it’s certainly not dangerous or excessive given the age of the car, and I doubt they’re obliged to do anything.
I’d take them up on their offer of cleaning it up underneath, but ask them not to paint or under seal anything. You can then carry on with the rust proofing and preventative measures others have mentioned to ensure its done properly.

Thanks for the quick replies guys, the dealer had very good reviews, mainly selling MX-5s, just wanted to make sure as I’m an MX-5 novice. I have been aware of rust, just wasn’t sure what to expect. This has put my mind at ease, I have already booked my car in with MX-5 Restore for an inspection with the thinking that I’ll go for the full underseal (that was decided even before I had the car as I’d like to keep it for a fair few years). Thanks again and hoping to see some of you on future meetings when it’s finally going ahead!

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Always surprises me that buyers never look under the car when they buy it. MX-5’s especially.

Due to lockdown I haven’t been able to test drive. Have been looking for a car for a while now, narrowed down the dealers to a handful who sells low mileage cars and specialized in MX-5s. The reason I jumped into buying this one, I noticed that there were less and less cars on the market (using the same search) and prices started to go up. This car has been passing MOTs without an advisory, 35k on the clock, plenty of close up pictures, reputable seller, serviced every year, last 5 services done by MX-5 restorer, so I put the deposit down and picked up the car with the view that I will get the underseal done. Judging by the comments above, it still is a good buy as it drives really well, looking great for a 62 plate and the rust is not over the norm. I guess I was just too eager to go for it, have been looking and trying to sell the idea to my other half for over 6 months, so once I’ve seen this I didn’t want to wait any longer.

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The pressed steel suspension components will have surface rust, that’s normal and are cheap and easy to replace when the time comes. As long as the main bits are intact then all is good. That’s what I was told before I had my NC rust proofed.

Does look tidy, if it’s been to the MX-5 restorer it should be in good condition. Just shame previous owner didn’t get it undersealed as NCs need it p.s. watch some of their YouTube videos of NC rust. They call themselves ‘Lights up, lights down’ on YouTube.

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Have the same car(soft top) in red have the same rust underneath having it cleaned and treated monday its just surface rust and will clean up
couldnt be ar zzz ed at my age to lie underneath with a wire brush prefer to pay somebody else :grinning: :grinning: :grinnin

g: :grinning: :grinning: :grinning:


Hi and welcome aboard.
Without wishing to alarm you The MX-5 Restorers have recently released a video on a very badly corroded NC.

Worth a watch as a cautionary tale. Get on top of the rust asap.