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Discussion Starter #1
Hello,

Thrust bearing in my 1988' 75 2.5 V6 is making rather annoying rattle.
The noise disappear when I press the clutch or just when keeping the clutch fork with hand.

The thrust bearing feels very loose on the bush/ guide pipe. Is it normal that there is a couple of millimeters between this bushing and bearing?

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I was wondering if that bushing could be wrong? I found three different part numbers for bushing (60518184, 60521878, 60518224 ) . Does anyone happen to know if these parts have different diameter?

The previous owner of the car told me that the gearbox was rebuilt using two other sparepart gearboxes, so I wonder if there has been parts mixed...

At first I was thinking that something is broken or loose, but when I finally opened the bell housing, everything seemed to ok to my mind (well, I'm still quite amateur with this car...)

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1631955


By the way, I did change the worn out fork to a new one, but it did not help with rattle.
 

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The sound your hearing may not be the release bearing. Every Transaxle car Ive ever owned (4) has a rollover (almost knocking or rattling sound) sound at idle, which is more pronounced with the clutch released. Although I cant put my finger on what makes the sound I believe it is either a) The driveshaft center bearing b) The clutch disc bouncing on the springs due to the driveshaft being elastic (Guibos) or c) the layshaft inside the transaxle.

I have never cared nor done anything to remedy the sound as 'they all do it' to some extent.

I also rebuilt my gearbox completely with mostly all new parts 3 years ago and the sound was still there after the rebuild
 

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Hi Peter

Okay so Brendan wrote
Every Transaxle car Ive ever owned (4) has a rollover (almost knocking or rattling sound) sound at idle, which is more pronounced with the clutch released.
This is true, most of these cars have this rattle to a greater or lesser extent, BUT some of them don't and none of them had it when they were new.

Below is a exploded diagram of the clutch. You see the washer labeled #18. It's described as a "Belleville" washer. I don't have a good picture of it but it has teeth that stick out. When it's installed it holds the throwout bearing in tension against the pressure plate fingers. I think as time goes on the washer collapses and the the throwout bearing begins to rattle.

I occasionally see NOS (new) throw out bearing on the European eBay pages, maybe you can find one with a fresh washer.
Chap 12  Page 6 Clutch.png

Hope this was helpful.

Bye
 

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Discussion Starter #4
You see the washer labeled #18. It's described as a "Belleville" washer. I don't have a good picture of it but it has teeth that stick out. When it's installed it holds the throwout bearing in tension against the pressure plate fingers. I think as time goes on the washer collapses and the the throwout bearing begins to rattle.
Many thanks for this reply, the belleville spring was indeed totally flat (I wasn't even thinking it as a spring but rather as washer) and definitely there was no tension againts pressure plate. Going to test to repair that and will let you know does it effect into rattle :)
 

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Hi Peter

Okay here are two semi-decent pictures of the belleville washer, installed on a throwout bearing but not on a clutch
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And Another
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Do you have a picture of your flattened washer? If so can you post it?

Bye
 

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Richard Jemison
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Generally such noise is the clutch disk splines having excess clearance on the input shaft, or the clutch disk`s "torque" springs being too loose, or weak causing it`s drive plate to rattle.
 

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Discussion Starter #7
Do you have a picture of your flattened washer? If so can you post it?
Too bad, no pictures but I happened to take a video of testing the clutch-flywheel package. You can see in the first couple of seconds of the video that I shake the release bearing and it is rather loose.


Anyways, I already bought a totally new release bearing, so hopefully it will solve the problem :)
 

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Very good, don't throw away your old throw out bearing. "Racingswim" on this board (and possibly others ) can rebuild them.
Bye
 

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Generally such noise is the clutch disk splines having excess clearance on the input shaft, or the clutch disk`s "torque" springs being too loose, or weak causing it`s drive plate to rattle.
On my car, clutch disk springs were loose and were tightened by a local rebuilder. Throw out bearing was also shimmed thigh. Two different transaxles and a number of different lube weights have made no difference on the rattle noise at all. I suspect loose disc splines might be it. The question remains however, assuming it is the clutch input shaft splines, what would be the fix? The clutch is not old or worn, but the shaft might be. There are no new input shafts, just old ones.
 

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Discussion Starter #10
Very good, don't throw away your old throw out bearing. "Racingswim" on this board (and possibly others ) can rebuild them.
Bye
Thanks for the info, I'll keep it in my storage.

And to the results...

In the end this was a slightly embarrasing. The belleville washer/spring wasn't actually flat but instead installed upside down and that's why it did not hold any tension :rolleyes: . I anyways installed the new thrust bearing, since the the old bearing was a noisy and the gap for the fork was worn out as well.
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Furthermore, there was some bolts loosen on the left side drive shaft, which I also tightened.

Finally, the noise itself is almost gone, but there when listening outside of the car, there is some rattle when car is on idle. But the rattle is much smaller, and can't be hear inside car. Also use of clutch is now more smooth.
 

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Hey Peter

First of, kudos for you for posting the solution to the issue. So many posts on the AlfaBB end with no conclusion.

Second
In the end this was a slightly embarrasing.
Don't worry these cars are hard to work on, there'll be plenty more opportunities for embarrassment in the future.

Bye for now
 
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