A few months ago my ND developed the well known rear hub bush problem - harsh ride, clunks and bangs and vibration when going over bumps (and also rather strangely when I switch the engine on). I took it into the garage and they said that the upper and lower trailing arm bushs were started to go, the others all seemed OK. I understand that it is not possible to get replacement rubber bushes so last week had them replaced with Polybush ones. However, this has hardly made any difference to the ride. The garage mechanic had a good poke around and could not find anything else amiss.
I’m not sure what’s going on. Do these types of bush take time to wear in? Should I have replaced all the bushes with the same type? Is there anything else that could be causing the problem?
If it knocks when you start the car it is nothing to do with rear bushes, As above plus check the power plant frame and all gear box and diff attachment bolts. Plus exhaust mountings and all clearances under the car.
Has the garage put the correct replacement bushes in, ie are they spherical bearings?
Hi, polybushes do not need to bed in, should be fine. The hubs have 6 bushes, 2 of which are the spherical bearing ones that fail. A polybush is not an identical replacement for a spherical bearing, however it will cure the knocking of knackered Mazda OEM ones. It could be one of the other bushes but unlikely. Could be a drop link, wheel bearing, shock absorber, exhaust mount. Def check engine mounts if it does it just by starting the car. Have someone help you by them listening in various areas whilst you start the car.
Thanks for the suggestions. I think the next step is to get someone to check all the various bolts, I didn’t think about the engine mounts. Just to confirm, the OEM rubber bearings and spherical bearings are the same thing?
But the Poly bushes that MX5 parts sell are just bushes, the spherical bearings are just that, a bearing in the outer carrier with no poly or rubber is involved.
‘Please Note: This bush kit has been specifically designed in blue to replace the original bushes that have bearings in them. They can not be swapped for the orange version.’ Lifted this from MX5Parts.
The originals have bearings in them but I think you are correct that these do not.
There is a chap called Andy that supplies ones with the bearings in them.
Hi TSM, the Mazda ND1 rear hubs have 6 bushes, 4 of which are conventional rubber ones, 2 are bushes with a spherical joint in them, often referred to as spherical bearings. The whole point of the hub having 2 spherical bearings is so that there are 2 known and fixed pivot points in the hub. A spherical bearing or joint, gives a fixed rotation/pivot point, 6 degrees of freedom. Anything other than the spherical joint does not possess this attribute. A polymer/rubber bush allows 6 degrees of freedom but is limited in those degrees of freedom and does not have a fixed pivot point. So the two are very different.
The Mazda spherical joints have a few flaws, and are best replaced with a proper spherical bearing design. If anyone wishes to know about such an item, message me and I can point you in the right direction.
Hi - thanks for the explanation, it’s all very complicated! I had a mechanic thoroughly check the car and he could find nothing else wrong, so I guess I’ll have to live with the problem. Very frustrating. I might try the bearings at a future date, though.
Hi, I’ve just bought my second MX-5 ND knowing that the rear bushes needed doing as one of them had already been fitted with a Polybush, so I got in touch with Brian McCloud and bought 4 spherical bearing bushes from him for £300 and they came with the complete fitting kit tool for free and with full instructions included, which is excellent value and a great friendly service. So the next fine day we get I’ll fit them.
Hi tsm, I understand that if this kind of thing is not what you are familiar with that can cause some apprehension. If you need further detailed advice/support feel free to pm me.
