Broken throwout bearing, Why?

What would cause this to happen? Less than 1000 miles on my super t-10 four speed in my Nova with all new Centerforce dual friction clutch kit with throwout bearing, new fork, new flywheel. 383ci with 425hp street car not drag raced. Trans started slipping and I thought I fried the clutch disc but now I'm thinking grease got on the disc, Also can the disc be cleaned with brake cleaner or should I just replace it with a new one?

 

It looks sort of like the throwout bearing spun and caught on the fork ends. That is just a wild guess. How did the bearing fit onto the snout of the trans ? Did it slide up and down easily ? Is the bearing the right one for the clutch setup ? Is the transmission aligned perfectly to the pilot bearing (using a dial indicator to check the bore on the bellhousing).

I would personally check everything and clean it all up spotlessly, put in a brand new disc, and a new TO bearing. You might get away with just cleaning the disc, but the gamble on having to tear it down again in the future isn't worth saving a few bucks.

Is it an optical illusion, or does the pilot bearing look worn sloppy inside ? I would send your picture to Centerforce via email and see what they think.

Don

 

Definatley talk to Centerforce .... they could have gotten their stock number messed up and sent you the wrong setup or maybe your info to them is wrong ... third possility maybe the bearing was previously dropped and cracked at the collar. Talk to the supplier.

 

There's really no force on that end. I don't thing you would even notice it driving.

 

Post a pic of the front of the trans with the same kind of detail. Looks like it was rubbing hard on the bearing retainer.

 

Is it possible the pedal over-traveled and the lip caught on the clutch fork, causing it to bind and snap off? That lip didn't just fall of, I think it was levered off by that arm.

 

The T/O have an odd shape, slightly egg shape where they snap into the collar. If you have the 'pointy' end facing the collar when engaged on the fingers the load isn't distributed even and that might happen.

 

That's what I was thinking. It looks like it got hot, there shouldn't be anything rubbing on that end.

KRH

 

Thanks for the responses, I will post some more pics today.

 

Some more pics from the front of the trans. I really dont see any place that it hit or got hung up on, no wear marks. Also this throwout bearing was new and part of the Centerforce kit. A good friend of mine who has a transmission shop helped me with the install and set this up for me using a alignment tool so everything was good from the get go. Or maybe not?

 

I'm going with that barring other developments, or a factory defect. Maybe they are Chinese now...

In the motorcycle world dry clutches commonly get oil soaked when primary chain oil level gets too high. Brake clean always works. In the old days we soaked 'em in gas and lit 'em on fire. Disclaimer: You should not do this.

 

My 68 chevelle has Super T10 & a ****ter Shield & I bought a heavy duty fork from the local auto parts.

I was cracking the sleeve which the T.O. bearing slides on though, Im suprized you didn't. The problem is the T.O. bearing hits the middle "web" of the fork. You have to grind the fork down a little bit in the middle.

THis area circled in the pix.

 

Your clutch pedal most have been sticky/hanging up/not smooth before it broke.

 

From what I see I have to agree with this. There does seem to be some galling on the bearing retainer on the front of the trans too. You need to polish that and make sure the new bearing slides smoothly and then clearance the fork as Mantaconcepts points out in his pic.

 

I had that happen in my 78 chevy half ton. It turned out when I had the clutch replaced by a friend, he forced the throwout bearing deep onto the fork and the fork did not seat into the ball seating correctly, and everytime I puched in the clutch it snapped a little more of the throwout bearing away. Just like yours. Was your clutch real hard to push?

 

Good ideas above. Try bolting the bell on your trans & check the fork movement & travel with that bearing

 

Some great info here, Im going to grind the fork as advised and bolt the bellhousing to the trans and check everything. Thank you all who have helped!!!!

 

Don't have anything to add that hasn't already been mentioned, but I still can't figure out what this is.

 

It is part of the Centerforce throwout bearing.

 

Yeah, make sure the fork snaps ON properly to the pivot ball with the retainer holding it on AND of course the whole fork & retainer both inside the T.O. bearing grove UNlike the pivot ball.

 

That's how I found the problem

 

It's a stopper to prevent the T.O. beraing from spinning on the fork & ware the fork out.

 

lot of people having problems with clutches lately, one thing i have noticed like somebody said, majority of parts are china, no matter who you get them from. i looked at a t.o . bearing a friend just had to change the other day for the second time and it was a cheap piece that he paid alot for, looked like it should have been on a 200.00 used riding lawn mower.

 

I think the issue I pointed out earlier is probally happening all the time. When you go to the local auto parts & they offer a "Heavy Duty" Fork, your gonna take it. If it "Heavy Duty", it's gonna probally be thicker metal & there's your interferance.