New clutch issue

[Benleroy]

http://www.apiberica.com/APIBERICA/Portada.htm

[Carsten]

Benleroy,

Okay, that's what i thought! And are we sure, that the cause of the rattle is the clutch itself, and not related parts as throwout bearing, carrier, flywheel bolts, pilot bushing, worn main drive gear, etc.??

The reason i'm asking, is that several people have put up good words for that specific company earlier, when i asked questions on quality of that brand, so just trying to rule out if their clutches are in fact bad quality, or if your problem lies elsewhere...

[echelon1]

Benleroy,

Okay, that's what i thought! And are we sure, that the cause of the rattle is the clutch itself, and not related parts as throwout bearing, carrier, flywheel bolts, pilot bushing, worn main drive gear, etc.??

The reason i'm asking, is that several people have put up good words for that specific company earlier, when i asked questions on quality of that brand, so just trying to rule out if their clutches are in fact bad quality, or if your problem lies elsewhere...

Going from the video the noise is coming from the clutch pressure plate ratling in the clutch bracket.
The wire spring system is doing exactly the same work as the clip spring type, but it does not pull the pressure plate away from the disk.
A disk that hit the flywheel bolts will show small lines cut into the bolt ends from the flywheel.(can be seen with the clutch removed)
You will also notice small damage on the disk where it has hit the bolts, usually at the sheet that holds the disk damping springs.
When observing the clutch disk with a strobe light conected to the engine, you will see that the disk is coming to a stand still when the clutch is depressed.( with gearbox in neutral)
This is a well working clutch, there should not be any drag that keeps the disk in motion.
If the disk is hitting the bolts, you will see the disk turning slowly while the noise is occuring.
A to tight bushing will also show a turning disk, and this gives the driver a small gear grind when shifting into first or reverse from a stand still.
Badly adjusted fingers will cause clutch chatter, as the pressure plate is unevenly pushed against the disk.
A bad clutch group will create the noise while the disk remains at stand still and the gearbox in neutral.
It will occur at a given engine RPM.( where the unballance is most effective)
Each and every clutch makes that noise, but it may not be obviously heard with the covers installed.
As wear increase, the noise becomes more appearant.
As soon as the clutch is engaged (clutch pedal released), there wont be any noise anymore as all the parts are under load.
A throw out bearing is silent when it doesn't touch the fingers.
A bad throw out bearing start creating noise as soon as it touch the fingers and start to turn.
As the driver put more load on the bearing while depressing the pedal, the noise will increase.

Hope this is of help in trouble shooting the issue.
My experience is that there are many bad clutch assemblys around.
I have seen them in red paint and other finish.
The best way to have a good clutch is to buy one from a well known American brand.
All others are copys, and copys are just that, not developed by experience...

Gindi

[Carsten]

Thanks, Gindi...most educating!

I know about the wear shown on flywheel bolts and clutch disc springs, if contact between them. My own clutch above showed clear signs of that, when I took it apart, even though no noise were heard when it ran. Guess the bolts and springs were already ground sufficiently down by hitting each other, to keep them from making noise.....

[echelon1]

Carsten, A freschly installed clutch that hit the bolts is noisy.
If the disk is installed new and does not hit the bolts with a thousand of a mm, it will not be noisy when it start to hit the bolts as it wears down.
The rubbing is so small and happens a thousand's times a minute that the noise is not detectable.
But as the disk wears, it wears on the bolts as well.
That's why you did not heard anything.
If the disk hit the bolts with a few thent's of a mm from the start, it has to cut in the metal.
As the disk is not a cutting tool, it slightly deforms when it hit the bolts and makes the air vibrating resulting in noise.
As the disk deforms, it can't completelly cut the material (metal) away, hence the noise persists.

Gindi

[echelon1]

There is no reason, ever, for the clutch disk to contact these unless they are the wrong bolt(too long) or split Lock washers have been used instead of 3/8 External tooth, or "Hi Nuts" have been installed and last of all the Clutch Disk is installed ass backwards causing the center portion to contact the nuts.

I would ad severall previous recurfacings from the flywheel to your list.
All above brings the disk closer to the bolts.

Gindi.

[Carsten]

I would ad severall previous recurfacings from the flywheel to your list.

Gindi,
There was actually an earlier thread on this matter, but i don't think we managed to resolve if there were any official specs to the minimum allowed thickness of the flywheel?

viewtopic.php?f=4&t=143657

[echelon1]

Hi Carsten,
There is no official spec for the flywheel.
A flywheel is made in order to fit the purpose from the machine or vehicle it has to drive.
For example : an agricultural tractor needs a lot of torque, the flywheel will be extremelly heavy.
A sportcar has a very light flywheel, as it is intended to work with a "short" gearbox with 5 or more gears.
A sportcar has to climb in RPM easilly, while an agricultural tractor usually works at a given RPM.
An engine intended to operate with an automatic gearbox will be made extremelly light, because the converter is heavy and bolted to the flywheel.
The engineers that created the jeep have calculated the flywheel that it has adequate torque, but still can easilly climb in RPM.
My point is that there is no real reason to waste a flywheel, as long as it can do what it is intended to do.
If the flywheel has been resurfaced so often that the clutch disk start to hit the flywheel bolts, it is out of spec...
If the mechanic can shorten the bolts and replace the loc washers with a thread locking product ( lock tite) , he can squeeze another lifetime out of the flywheel.
Luc's suggestion to measure the flywheel depth and compare with the clutch disk is the way to go.
A clutch disk differs from brand to brand, hence it is always good to measure things up before installation.
One must take flywheel wear, and disk wear in consideration before giving it to a shop for resurfacing.
Flywheel wear can be measured with feeler gauges, and a disk is worn when the rivets that keeps the friction material on the disk plate start to rub the flywheel or pressure plate.
So it is an easy calculation to find out if the flywheel is usable or not.

Gindi

[Carsten]

Thanks, Gindi....

[Benleroy]

Here's some news.

This week we've put the cover on the bell and the body and the sound is really minimised.

In the same time, the friend who had the same issue may have found a solution.
According to him the problem is from the pressure plate on the mechanism. His plate may have not been equilibrated correctly at factory.

I'll ask the question and show the movie to the dealer who sold me the clutch mechanism this saturday. I'll keep you informed.

Best regards and many thanks for your help
Benoit.

[echelon1]

Thanks for the heads up Benleroy.
Past week someone came to me with a jeep, I heard his clutch ratling at idle and just above idle.
He didn't bother, and as you said the noise is minimal with the covers installed.
There are no side effects, actually his clutch was smooth.
I felt a much lighter clutch pedal, with the linkage installed correctly.
That's a big difference with the M38 clutches that seems to have heavyer springs.

Gindi

[Benleroy]

I was this weekend at my dealer shop.

I've asked about that noise to "Marino" the owner of the "Stock des ardennes" at Salmchateau (Bulge).

He explained me that this noise is quite normal. Last year a customer made him remove his clutch 3 times, he put a new one but the proble seems present each times.

He asked to the factory and they said that it's totally normal.
People nowadays wanted a jeep without any noises with a technology of 70 years.Once the cover is placed the noise is nearly inaudible.

In short: this is normal.

"your clutch is working well, right?"
"so stop thinking and ride"

According to him the noise comes from a steel lug at a finger.

[Gustl]

Thank you for this update, Benoit!

Here's some news.

This week we've put the cover on the bell and the body and the sound is really minimised.

I did reinstall inspection hole cover and floor cover too this weekend. Also placed a cork gasket between tub and floor cover. Since then it shifts like automatic (compared to before). Marty already told us in an earlier thread, that the noise will be less nasty once the covers are on.

Also thanks for your dealer´s input

Cheers

[Benleroy]

Absolutely Jean Marie.
I am not satisfied with his answer, but I think he's honest. I think the problem come from the tolerance of the piece.
I've decided to restore my old clutch mechanism and replace it next winter.