- My model of MX-5 is: 2010 NC2 PRHT
- I’m based near: Cardiff
- I’m looking for technical help or recommendations on: Suspsension knocking sound as below
Hi all, my NC2 Sport Tech PRHT has developed a knocking sound from the front. It is most noticable at low speeds (up to 30mph). It happens on any road that isn’t perfectly smooth and knocks when there’s any imperfection in the surface. It doesn’t seem to be triggered by going over speed bumps though.
I had drop links replaced all round in February, and I’ve just replaced the anti roll bar D bushes but it’s still knocking. I took it to a couple garages but both weren’t able to determine the cause, one has said “possibly shocks”, while the other said “possibly lower arm”. I know it’s vague but is anyone able to determine from the video what the knocking could be. I’d rather be able to determine the issue instead of using the “parts cannon”.
Video of knocking sound: https://youtube.com/shorts/aUKncUhoRMY
Having watched the vid, it appears the knock comes as the centre of balance of the car is transferred left and right from dead level.
I’m surprised that the garages cannot pinpoint this because enough poking and prodding will get to the bottom of it.
At least ARB links and bushes can be ruled out.
I’m thinking possibly front shock assembly top mounts would be worth investigating before going back over the other suspension parts more thoroughly.
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Off the cuff thought but have you recently had the front pads changed ?
My mate had a knocking and we went through the usual suspects on the front end.
Eventually we changed the front pads again for another brand - and the knocking went away.
Thanks. Bit more googling says others have replaced shocks and noise has gone away. I’m looking at coilovers all round anyway which might mean I’m getting a (very) early birthday present to myself.
Which is due anyway since the first garage said rear shocks are blown as well. 15 year old shocks and 70k miles means it’s about due
I’ve not had front pads changed recently, no. I was having a clanging from the rear a few months ago and that was resolved by changing the rear pads, but that was noticable under braking, this one seems more consistent with a suspension issue.
Probably the front drop links on the ends of anti-roll bar. Not too bad a job to do and about £35 for parts.
Even though they were replaced in February all round?
Well, february was a few months ago… Sometimes parts are defective or get damaged when fitted.
I would say it sounds more like a control arm than a shock butI would check the top mounts of the shocks, make sure the bolts are nice and tight. If it is shock related I’d say it’s definitely something loose or perished bushing, not necessarily a defective shock. Check the bolts and bushings on any parts that were replaced; if they weren’t torqued or retorqued, especially if the proper nylock nuts weren’t used, then they could be the issue.
Can you make the noise just by leaning on the car and pushing or pulling it up and down? From the consistency of the knocking, unless you have an object loose in the car somewhere that is bouncing around, it sounds to me that either something is loose and needs torquing, or that a rubber bushing has perished. Jack the car up and give the wheels a good yank around to feel out any play that might be there, that might give you a clue as to what’s wrong. If you have another jack or something that you can use as a lever, when the car is jacked up, put blocks under one wheel so the whole car doesn’t rock and try and move the unblocked wheel up and down with another jack or lever.
Lastly, are you getting any vibration in the brake pedal and does the noise continue at higher speeds?
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Nothing in the world wears out like droplinks- they’re under a lot of stress (and they’re also easy to damage slightly during fitting). Plus cheap ones can really, really suck. So it’s a good place to start but in the video it just doesn’t sound quite right for a worn droplink, they tend to “tap tap” rather than that deeper knock.
Your garage should have done this already but I’d start with a nut-and-bolt check. It’s all easy stuff, some of the access is fiddly but we’re not even looking for perfect torque here, just “tight or not” so very diy’able. The sound is very like what you get with a straight-out loose part, knock not tap.
On the sound alone it is also a bit shock-ey. Bushings tend not to be knockey unless they’re very worn (because even mangled rubber still damps). The ball joints on these cars seem pretty durable, unfortunately that’s not quite as easy to check as you basically have to remove that end of the arm out of the hub to test.
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Have you had a wheel alignment carried out at all? If so, are the align bolts properly tightened and fully nipping the bushes? I’ve known rust build up to make it seem that the bolts are tight but actually, the arm is moving slightly in the subframe.
3rd garage: Identified the problem was front nearside drop link, it was replaced and now the noise is gone!
You guys were 100% right, drop links are made out of match sticks. @Dipstick @Northwind @Ron_Damage
Few lessons learned: sometimes the simplest answer is the answer. Kwik Fit
is better than Halfords (the branches near me anyway). Drop links are really weak, I suppose this could’ve been from hitting a pothole!
£85 total to fix, not too bad.
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