Throw-Out Bearing Clips and hat they do?

[hohieu]

I know it's been the experience of seasoned veterans on this board that these clips fail. But I'm wondering if a failed throw-out bearing takes out these clips and not vice versa.

 

I've been emailing with a fellow board member who brought up a really good point about these clips. There's really no free play in the clutch fork so the T-O bearing is pretty much always loaded, and this load of course, increases as the clutch pedal is depressed. The tabs on the back of the throw-out bearing wedge up against the sides of the clutch fork and would prevent the bearing from from spinning on the snout of the tranny.

 

I'm wondering if the role of the clips may be to merely hold the bearing on the clutch fork during assembly.

[lmdew]

Yes, they hold the TO Bearing to the fork. The TO bearing is not up against the pressure plate all the time. With the cable clutch you should have about a 1/4" of free play.

 

The Hyd clutch should also be fully releasing pressure in the TO bearing.

[hohieu]

Ok, I was under the impression that on hydraulically actuated systems, the angular contact T-O bearings were in constant contact with the spring fingers of the pressure plate.

[davebugs]

Lets put it this way. If one is broken I can buy the car awful cheap.

 

And they should be mandatory in my opinion when doing a clutch job. For a few bucks they are in there deep, just replace them.

[idosubaru]

But I'm wondering if a failed throw-out bearing takes out these clips and not vice versa.

you are more versed about them than I, as I don't know the technical stuff about clutches but i'll share my experiences and the two issues i've seen when pulling motors/trans:

 

1. missing one clip on a perfectly functioning vehicle. i am just assuming the clip failed (somewhat based on #2) but who knows, maybe something caused them to fall off like you're suggesting. ;

 

2. aged clips that are...not rusted...but the metal just looks aged, the surface is not clean looking....sort of, hard to describe but they're notably fatigued and i wouldn't want to leave them in there.

[hohieu]

I know you fellas have looked inside of the bell housings on many, many more Subarus than I. Grossgary, thanks for detailing your observations.

 

There's really no free play in the clutch fork so the T-O bearing is pretty much always loaded, and this load of course, increases as the clutch pedal is depressed.

 

I was wrong about this, there is some free play in the clutch fork. As Imdew mentioned, Subarus have standard t-o bearings that are not in constant contact with the spring fingers of the pressure plate. So when the clutch is engaged (clutch pedal is up), the clips hold the clutch fork and T-O bearing together. But these clips don't take that much load because the fork doesn' pull the t-o bearing back over the snout when the clutch pedal is released. Instead, it's the fingers pushing the t-o bearing and attached clutch fork back.

 

I'm just wondering what prevents the front of the bearing from contacting the pressure plate when the clutch is engaged because there's no return spring on the clutch fork.

Edited November 4, 2011 by hohieu
clarity

[WoodsWagon]

It touches it, but there's no load on it.

 

If either of the clips fail, then the throwout bearing starts rattling on the release fork and the snout (quill) of the transmission. The throwout bearing is steel, and the quill is aluminum, so it wears a pretty deep area out of the transmission housing.

 

The clips break first, and they break from fatigue rather than excessive stress. The spring steel work hardens and then shears.

[hohieu]

Thanks WoodsWagon, that really clears it up for me. My old clips appeared to be in pretty decent shape, but I guess you can't really see fatigue.

 

On the other hand, the clutch fork retainer spring was pretty worn where it contacts the pivot ball. I'd probably consider replacing it the next time I'm in there.