MX-5 OC Forum

 Hi All,

I wonder if you can help. I have recently purchased a MK3 and apologies if I should already know the answer to this and if this car behaviour is perfectly normal. When I have been driving the car, stop at say some traffic lights, put the car into neutral and release the clutch all is normal however when I engage first gear there is a noise that I can only describe as a "clunk". Someone mentioned an ABS test to me but I thought this would be when the car is first started (start-up ABS check). I am not sure so I wondered if you can confirm what the situation is.

Any help would be much appreciated and if need anymore questions for me to clarify I will do my best to answer these.

Ben

Sounds like the clutch might be dragging, possibly slave cylinder leaking.

Is the bite point particularly low?

If you keep it in gear while stationary with the clutch down, does it begin to creep after a while?

 Hi - I am not an expert but don't believe the above is an issue. For some reason I think the noise could be coming from the back of the car which leads me to suspect it's ABS or something?

 I agree with Victor on this 

ABS is a passive system in that it only releases brake line pressure. On some cars if you start them with your foot on the brake you can sometimes feel a push as the system does start up checks (usually wabco systems). What you are hearing is driveline lash being taken up due to a dragging clutch. Either the hydraulics are on their way or the adjustment is wrong (Thread about poor gear changing on here explains more).

Thanks for the reponse guys, although I am a little worried now. Is there a lot of work involved to get this corrected?

The other problem is it doesn't happen all the time and I can't identify a pattern apart from when I have been driving for a while, go into neutral, disengage the clutch, put the clutch down and engage first again. The slight clunk happens just before 1st or even 2nd is engaged from stand still?

It definitely sounds like clutch slave cylinder starting to go. It's a relatively easy/cheap fix...and a fairly common problem on all cars with hydraulic clutches.

A couple of other symptoms would make me more certain. If, when it happens, you pump the clutch a couple of times and it goes away - and/or if you leave it in gear with the clutch down, the car starts to creep forward after a while, and/or if you are slowly losing hydraulic fluid from the reservoir, then I'd put money on it.

If you're not the sort to do your own work, a mechanic will be able to tell from looking at the slave cylinder as he'll find fluid on the shaft / in the rubber boot.

Thanks for this I will definately investigate. How much work are we talking here and what cost should I expect (is it a complete new clutch?)? Apologies but as mentioned I am a bit of a novice.

Ben

Oh no, less than an hour's work plus the part - an aftermarket slave cylinder is about £40 from mx5parts.co.uk.

Please don't go booking it in until it's properly diagnosed though... Where in the country are you?

Thanks -  I am based in Luton, Bedfordshire does this help?

Unfortunately not, I would have recommended someone to have a look for you if you were nearby.

Someone mentioned to me that this also could be the diff engaging? Could this be the case?

It won't be the diff engaging! You need to have unequal wheel speeds for that and LSDs don't usually engage with a clunk, locking diffs do though and you have not got one of those. The noise you are hearing is drive line slack being taken up due to a dragging clutch.

Davebrg posted earlier this week about a specialist around your neck of the woods, try searching his posts, as I live in kent I didn't pay  much attention I am afraid.

Thanks, I just spoke to my father and he confirmed something similar. Again apologies for my lack of knowledge but the dragging clutch relates to the slave cylinder right? Also just to confirm perhaps "clunk" is a too strong word, it may be better to describe as light knock.

Cheers

It's caused by the cover plate not releasing enough. can be slave or master adjustment, it's not usually a failing  master but can be. It can also be a build up of friction plate dust on the splines of the input shaft to the gearbox.

deflepps:

Thanks, I just spoke to my father and he confirmed something similar. Again apologies for my lack of knowledge but the dragging clutch relates to the slave cylinder right? Also just to confirm perhaps "clunk" is a too strong word, it may be better to describe as light knock.

We can't diagnose your car's problem for certain over the internet with a description of a noise. What we can do is give you our best guess at the most likely cause of it, and either suggest an approach to diagnose it yourself, or some idea of what a mechanic is likely to tell you if you will get a garage to sort it.

The very first thing I would do, in my 15 years experience of keeping cars on the road myself doing my own work, is to have a look at the slave cylinder to see if it is leaking. If you (as it sounds) are not likely to do such work yourself, then you may as well just go to a garage and ask them what the noise is...and most mechanics would diagnose it in the same way.

Edit: Just to be dibbly doubly clear - this is not a normal noise and there isn't a straightforward explanation for it. Something is wrong.