I’ve just bought a 1994 MK1 Eunos which is making a grating / grinding noise when the clutch is pressed when in gear. The sales guy assured me it was the clutch bearing and would only cost about £50 to fix, however I don’t trust sales-people too much so would appreciate some advice:
It doesn’t happen all the time, and happens less the more I drive the car
It only happens when the clutch is pressed, during normal driving everything is fine
In all other respects the clutch is fine (it bites where I’d expect it to, there is no slippage, etc).
Any ideas welcome (before I take it to the local mechanic who will no doubt want to replace the entire transmission !)
The sales guy is pulling your middle leg. Given that the release bearing will cost about £20, I very much doubt that you will find anyone that will remove and replace the gearbox and clutch assembly properly and with due care and attention for £30. If you do find someone then please let me know and I will book my car in for a new clutch ASAP. It could also be the spigot bearing that is noisy. These cost less than a tenner new but again it is a gearbox-off job to replace one.
Given the amount of labour involved it would be a false economy to replace the releas or spigot bearing in isolation. A 1.8 clutch kit supplied and fitted would cost around £220 (MX5 Motors in Doncaster). Add another £10 for the spigot bearing since these are not supplied in a 3-piece clutch kit.
If all other aspects of the transmission are OK then I would just live with the noise until such time as the clutch plate needs replacing or gear changes become difficult.
If the bearing is truely failing then the input shaft will slow down and make gear changes difficult. If it gets to the point where you are crunching gears frequently then I would consider sorting it out before the gears and synchros become damaged.
TBH, just about every car I have ever owned (including some new ones) has exhibited transmission noise to some degree. Without hearing how bad yours appears to be it is difficult to advise further. You could try a local MX5 specialist for an opinion:
You won’t get an immediate response from Carl or Steve in this thread (since they are not participants), but think about it, if the release bearing is not spinning freely then the input shaft will start binding when the release arm touches the outer race of the bearing.
The input shaft is turning at engine speed , you depress the clutch pedal, the clutch disengages and the shaft stops , if the spigot bearing is failing this can have a binding affect on the shaft and the shaft could then turn.
Thank you all for your input, I realise it can’t be easy diagnosing “noise” problems when you can’t actually hear it happening.
If I could just clarify, the noise is a constant rattling / grating / grinding noise when the clutch is presssed when in gear, not just clutch-pedal noise (if you know what I mean !)
yes that sounds like the bearing. If I can help you with costs, I was looking at having the clutch assembly replaced, my local garage costed it as £190 of labour to do and it will be a tiny reduction in labour to not change the clutch. the clutch assembly with bearings @ £85 upwards. Some specialists will do the whole job for @ £230 including clutch.
Being a bit cash flow challenged and lacking in spare time with the last days of summer out there I had the local Mr Clutch replace mine and for £230 they did a good job, it took them @ 5hours and its a Exedy one they fitted and to be honest they were very attentive to the car took an interest in it etc. In short the guy doing it was most interested in the car. And the old clutch was well and truly past it.
As for the bearings all I can say is it no longer slips and the changes are smoother so something is dragging less.
You said in your first post the clutch bearing would slow down the shaft , the object of depressing the clutch is to stop the input shaft turning to allow gear changes . In reply to your last comment, the thrust bearing has No connection to the shaft unless it breaks free from the thrust fork or the diaphram colapses and allows the thrust to move forward so far that it may possibly touch the shaft, which in both cases you would have not be able to engage or dissengage gear without undu force .JJ.
Surely it is important that the release bearing is centred with respect to the diaphram spring fingers on the cover plate? Given that the release bearing is attached to the end of the lever arm and the end of the lever arm moves in an arc, how does the release bearing remain centred with respect to the diaphragm spring?
Thanks for the insight. Until now I was under the impression that the clutch needed to be disengaged so that the gearbox shaft speeds could be synchronised (with the help of the synchromesh rings), although I am still struggling to see how this can be possible if the input shaft is stopped dead.
Guys one of the things I like about this forum is its helpful without the spats that bring forums down around the internet. So do the finer points of clutch design and operation matter?
To try and help the original poster could we agree that MX5’s are prone to having noisy clutch release bearings and that a certain level of noise is irritating but not serious and if you get an expert to check it over you may be OK. But a bearing that is close to failure ought to be replaced. If it needs replacing then it is a gearbox off cost and the labour is about the same as changing a clutch, and so if you do have it done then you may be as well to just get a new clutch at the same time.
Me I always though that one side of the bearing was connecting to the clutch lever and the other the clutch cover which is often rotating at engine speed, so as you press the clutch pedal down the bearing has to push against the diaphragm spring thingy and so is under load and any wear etc will make a noise. I could well be wrong not having dedicated a significant period of time to study of said topic. And on MX5 ones having looked at the list of tasks in the manual I chickened out of changing mine so a bit of a woose and happy for both of you to shake hands then pick faults in my description.
The input shaft is splined and locates with the clutch driven plate (friction disc). This input shaft rotates inside a smooth tube and the clutch release bearing slides up and down the outside of this tube so the two do not come into contact with each other. Usually when a clutch bearing fails it is more likely to seize/break up and damage the diaphragm spring fingers of the clutch cover plate. Hope this helps.
