front suspension knocking

hi all, i have a knocking on the front suspension which only happens on relatively bad roads the previous owner (my brother in law) tells me he thinks its the damper but im not convinced it only passed its mot last weekend with this problem. any advice greatly appreciated.

It could be the anti rool bar links.

Was there anyting loose when you were under the car to inspect it.


  Hi  Welcome to the FUN

  ARB drop links have a lot of work to do on most vehicles. You don’t say which MK MX5 you have but on the MK1 the drop links were/are a bit agricultural and as such not really suited to a car that has a sporting nature. Mazda addressed this oversight by changing to ball jointed rod linkages on the NB and onward.

  The ARB drop links on my MK1 were becoming almost a service consumable part at MOT time as they just failed so regularly. I decided to make me own and added in full adjustment for good measure. The result is that in the last five years my drop links have shown no problems and entertained me by allowing adjustment in the ARB preload. In contrast the first five years of ownership saw three replacement sets of ARB drop links to pass the MOT test.

  If you have an NA you could put nyloc nuts on the link bolts with lots of copper slip grease in the bolt sleeves and do the nylocs up only enough to loose any play in the joint but allow the rubber and sleeve to move freely together instead of having constant twisting and loading of the bushes. It’s similar to fitting poly bushes but without the cost. Heres my ones anyway.


NB link on the left NA link on the right.

NB links cannot be fitted to the NA but NA links can be fitted to the NB 


There was a post the other day about suspension clonking. I reported that my MX5 had the same fault.
Taking it for a full service and MOT today and will mention this as well.
Will report later on any findings.
Just hope it’s nothing too expensive!


Suspension knocking can be a pain to diagnose unless it is pretty serious.

Chances of something being loose enough to spot while the car is up in the air are often slim - and you can guarantee it will fail to present itself consistently should the mechanic go for a drive (they should unless it is obvious…).

Anti roll bar drop links or bushes are a firm favourite for the majority of minor suspension knocking, especially if the handling does not feel compromised.

From past experience on a number of cars, a worn ARB link tends to knock or rattle when the car is travelling straight ahead, especially when the steering is straightened after a bend, or changing from one lock to the other. This is because the links load up when cornering, which tends to stop the rattle.

so ive done some road test regarding your advice especially hard cornering im getting the knocking under all conditions any more advice will be greatly received.


 Have a look at the exhaust system. Check by giving the tail pipe a good shake side to side. If you hear anything then you’v probably found your problem.

its defo not exhaust system i feel the knocking through the steering.

It could be one of a number of suspension joints but but another thing to check is the track rod end joints. Get an assistant to move the steering wheel from side to side while you hold the joint. Any lost movement at all means the joint needs replacement. I’d do both because the tracking will need a check and adjustment afterwards.