What's This Noise?

[madmoomoo]

Hey folks,

I had my clutch replaced about a year ago (for an exedy HD one). Since then there has been a little bit of noise, but it's getting quite loud now and sounds rather ridiculous. I don't know much about clutches, but I really want to get rid of this embarassing noise.

The chirping is there when my foot is not on the pedal, then when I step on the clutch slowly, the noise gets higher pitched then ceases when the pedal is about half way down.

I've recorded this stupid noise from the drivers footwell. I basically had the engine running and was slowly pushing on the pedal then off again a few times.

Can anyone diagnose my prob from the sounds? Then how do I fix this silly noise?

thanks in advance.

clutch_on.off.mp3

[Links]

Ahahaha.. sounds just like mine.. I can kick the clutch in a little and it goes away.. than comes back.. than goes away.. my thoughts are that it is the thrust bearing not sitting right and wobbling.. does it increase with revs??..

As soon as you put pressure on the clutch it is moving the clutch fork and grabbing the thrustbearing and stops it from wobbling.. that's my thoughts anyways.. might be wrong.. but mine did that after I put in a different clutch from the stock nissan one..

[madmoomoo]

Yeah, the sound increases speed with revs. If it's the thrust bearing though, wouldn't the sound only be there once you started to press the pedal? I'm not really sure of the mechanics of it, but do you know if there's anything i can lubricate to get rid of the stupid noise?

[Links]

At the moment I haven't done anything to fix it..

the whole thrust bearing will be spinning freely I believe when the input shaft is spining as there is nothing putting any pressure on it..

it's different to when the bearing is worn, as that noise happens when the 2 sleaves spin at different speeds and the bearings rumble..

I believe the whole thing is spinnng freely but possibly off balance or it's rubbing on something..

[Chris_R33GTSt]

Yeah, I have a '97 R33 S2 GTST with 60K genuine on the clock.

Aside from a 3" cat back HKS system and a Blitz pod it is completely stock. I am led to believe it has had an easy life.

I have the same squeaking noise when in neutral and it goes as soon as i lightly depres the clutch. It is driving me insane.

The car is still under warranty - is this something that I should get fixed?

Does anyone know how to fix this?

Edited July 25, 2006 by Chris_R33GTSt

[mad082]

is it a single plate clutch or multi plate?

but it just sounds like the input bearing. once you put heavier clutches in it puts more strain on the bearings.

[Chris_R33GTSt]

Nar,

The car is standard and has no modifcations (other than simple cat back exhaust and pod). It is as it left the factory.

I will be putting a heavy duty clutch soon as I dont think it will last much longer once I start increasing the boost

Edited July 25, 2006 by Chris_R33GTSt

[mad082]

when you get the clutch done make sure they put in new bearings, and check the pivot bolt. get them to remove it to make sure it isn't cracking at the base (where the thread meets the body of it). and hope they don't ever tighten it when they put it back in. when mine broke my mate who is a mechanic told me that the most common cause of them breaking is being over tightened.

[Chris_R33GTSt]

Dude,

Thanks heaps for the advice - This is my first skyline and i have had it for less than a month. I dont know much about it yet (Last car was a 91' liberty). I still have 2 months of warranty left so im thinking about getting the dealer to at least cover the labour on getting the new parts in.

Hopefully il be able to make the next big cruise too - as long as the car stays in one piece ;-)

[madmoomoo]

If nothing is cracked or broken, is there a way to lubricate the suspect bits without pulling the gearbox or anything out? (I remember a little rubber boot near the clutch assembly. can I get to the right bits through that?)

It seems this might be a semi-common thing?

[mad082]

no you cannot get to the bits without taking the box off. the input bearing is on the engine side the flywheel.

if you went through the rubber seal around the clutch fork you could possibly lube the throwout bearing... if you were a really good shot. all you can really lube from there is the pivot bolt.

[Zahos]

Sounds like spigot bush (I think it's also know as input bearing - correct me if wrong).

I've been told that once it's worn, the input shaft can have too much play, and makes those sorts of noises (mine did it - not as much as that though - just before i last changed my clutch).

I don't know if there will be any negative consequences from leaving it, but i do know how annoying it is.

The bush itself costs less than $1 from memory, but takes a bit of effort to install.

[mad082]

The bush itself costs less than $1 from memory, but takes a bit of effort to install

like my pivot bolt. cost me 90 cents to get it fixed, but took me a few hours to get the box off and back on.

[Links]

Thrust bearing/Throw Out bearing are the same thing.. input shaft bearing is different.. it's the main bearing that the input shaft sits in and is between the shaft and the gearbox housing..

The noise I believe is from the thrust bearing/throwout bearing..

The input shaft bearing will make a noise at the same time, however slightly depressing the clutch will not make it stop..

If you are slightly depressing the clutch and it goes away than it is probably the thrust bearing.. usually happens when you put a new clutch kit in..

If the whole car is under warranty - get it fixed.. they should pay for it all that's the deal.. if it isn't.. unless it's driving you nuts.. i'd leave it.. when it's gonna cost you aroung $400 to pull the box down I don't believe it's worth it.. The bearing isn't rumbling.. it's just squeaking..

Also - changing the clutch won't fix a worn input shaft bearing.. they have to re-pressed to fix that..

Edited July 25, 2006 by Links

[mad082]

the input bearing can stop making noise when the clutch is pushed. when you push the clutch in it takes load off it, and it is just being driven by the engine (no sideways force).

the throw out bearing usually starts making noise when you push the clutch in (from the moment it starts putting pressure on the pressure plate), and keeps making noise until the gearbox stops spinning. we replaced the throw out bearing in my mates commodore because it was making noise when the clutch was pushed in, but not when it was let out. all good now.

bearings usually make more noise when they have pressure on them than when they are free spinning. and the input bearing is getting sideways load of atleast 800kg (clamp load of the clutch)

[madmoomoo]

So do you guys reckon there's any way to get to the offending bearing with something like silicone spray with tube or bit of wire with grease??

I guess there may be no harm in leaving it, if it is in fact a bearing as you guys suggest. it's just annoying.

If I were to try lubricating what I can get to, would there be any danger of missing and stuffing something up?? (obviously don't want to lubricate clutch plate face... but anything else?)

(I wish i had the resources to pull the box out myself. One of these days I'd love to get the chance to)

Thanks once again for all the great feedback. Hopefully I'll be able to get some sort of resolution. If not, at least hopefully I'll learn something about clutches.

cheers.

[mad082]

you won't be able to get to the bearing without taking the gearbox out.

you don't need a huge range of tools to take the box out. just some jack stands, a trolley jack (a cheap 1 will do), some spanners, a socket set. i think thats all.

also good to replace the oil when you do it. drop the oil out before you start working on it, then fill it up when you are done. makes the box a bit lighter.