Explanation of Clutch Mechanics

[CBRRICH]

I recently had my original clutch replaced at 130K on my 05 GT wagon by a local shop (not dealership) using Subaru parts. Two months after installation the throw out bearing (TOB) started making a chirping noise that would stop if you would press in the clutch pedal an inch or more.

 

The shop figured they had gotten a bad TOB and replaced it, two months later the same thing. This time they replaced the clutch slave cylinder, that did not fix the problem.

 

I researched all the components and looking at the exploded clutch slave cylinder it has an internal compression spring. That would imply it keeps pressure on the clutch fork all the time and therefore presses the TOB against the pressure plate springs. This would cause the TOB to spin 100% of the time, does not make sense to me.I would think there would be "0" contact (similar to brake hydraulics).

 

I was not able to find anything in the other threads that matched this exactly. Anyone have a different interpretation on how this is supposed to work or had a similar experience with the TOB they were able to resolve?

[Shadow_419]

The spring keeps the components in light contact but once the pressure plate is at rest there really isn't much force being put on the bearing. I mean it is a bearing and spinning is what they are made to do.

 

Without the light spring in the slave cylinder there's a shock to the components when you step on the clutch. With the spring, everything is snug and aligned for the next time you press the clutch.

[MilesA]

Check this thread, not sure if it matches your situation, but good info in any case.

 

http://legacygt.com/forums/showthread.php/why-not-drive-dyeing-clutch-tob-horrors-inside-186387.html

[CBRRICH]

Thanks for the explanation. The TOB is new and shows no wear.

 

The shop has the clutch apart and the only thing they can find is that the dual mass flywheel is not returning to center. Supposedly, it was not doing that before they resurfaced it. It's been ~10K miles. I still suspect the pressure plate is not true and "wobbling" the bearing.

 

The Flywheel is almost $600. Does anyone have any idea how long they are supposed to last?

 

I know they have 2 failure modes I could find: the center bearing (which this could be) or the springs/contact points wear and there is slop. If it is truly hanging up, the bearing may be going and I'd be best to suck it up and replace it now. I just thought they were supposed to be good for (2) clutches (~200K).

[Shadow_419]

Could go single mass flywheel.

[sigmafour]

you can't resurface dual mass flywheels. It's now junk.

Go single mass as shadow says.

 

https://www.phoenixfriction.com/t-dual-mass-flywheel-resurface-replace-convert.aspx

[CBRRICH]

The shop gave me a new dual mass flywheel with installation for $400. They have tried to make it right. So far so good. When they pulled the flywheel was it was "locked" in a rotated position. They said this was pretty unusual to see it get stuck. Either way it had to go. Not sure how that would make the throw out bearing noise but maybe it was not the TO bearing all along but the flywheel itself?

[Max Capacity]

Your not the first to have a DMFW do that. There have been threads with pictures on here over the years.

 

Most of us go with a SMFW. Subaru did in 2007.