Update on thowout bearing failure.

[rhipsher]

Another throwout bearing bites the dust. This time not only did the bearing break but the wire ring that attaches it to the flex plate popped clean off. Lee brought over an Ac delco throwout bearing and upon comparing it to the Luke one the Ac delco square fork plate is almost twice as thick as the Luke one. Just a rediculous little wire ring is all that holds the throwout bearing to the flex plate. I decide while I'm at this point just to go ahead and order the Fidanza flywheel. So if any of you guys have to replace the clutch take a little advice from me and don't use the throwout bearing that comes on the Luke or Valeo clutch kits. Use Acdelco. The fork plate is much thicker even though both are made in china.

[A26B]

Check the fit of your throwout bearing onto the trans input shaft housing. Something is definitely not right here. To destroy the throwout bearing(china/taiwan or other) like that is way too much release force on the bearing. The retainer spring is not under any pressure when releasing the clutch. It only holds it in place. If the throwout bearing binds on the input shaft housing during trans install, then the bearing retainer spring can be forced off the bearing.

[rhipsher]

Originally Posted by A26B

Check the fit of your throwout bearing onto the trans input shaft housing. Something is definitely not right here. To destroy the throwout bearing(china/taiwan or other) like that is way too much release force on the bearing. The retainer spring is not under any pressure when releasing the clutch. It only holds it in place. If the throwout bearing binds on the input shaft housing during trans install, then the bearing retainer spring can be forced off the bearing.

Yeah I agree Jerry! But is it possible for the slave cylinder to exhert enough force to push on the clutch fork hard enough to break it? Everything fits fine. Jerry there was enough force that it snapped about and inch of the slave pin off. I'm interested to know how many members are running a stock clutch. I can't be the only one that this has happend to. I did the clutch a year ago and installed everything correctly. It all went together like butter and ran fine. This happened to the clutch that was in the car when I bought it so I don't see how it could be something I caused or installed incorrectly. I think monday I'm going to give Bill Bouxdro a call and see if there's some voodoo black magic secret I'm over looking.

[jonszr1]

just a thought .could there be a problem with the bell housing.maybe its a factory flaw ??????? anyone had a problem like this ????????.but maybe i am nuts .

[LT5-Lee]

Rick, I need to correct you on the mfg. of that throwout bearing. The one I brought over was just in the GM box, it is NOT th3e throwout bearing from GM. I previously bought the GM one ($90?) and decided to use instead of the one from china.

The one I brought over came in the Valeo #52802206 clutch kit and is the lower bearing lip in the pic.

[LT5-Lee]

I noticed the back side (engine side) of the clutch fork directly behind the slave cylinder dimple has very sharp edges and it dug into one side of the bell housing. It had to be pressing into the bell housing at an angle. I forgot to get a pic of it.

The transmission input shaft nose didn't look bad or have any noticeable resistance to the touch and the throw out bearing wear pattern also looked fine for smoothness & engagement length.

[LT5-Lee]

BTW, the cheap-o transmission plug from Harbor Freight worked great to plug the back of the transmission output shaft for a no oil loss and they also have their 800 lb. transmission jacks for $99. I made a few additions to mine and it is not a super high quality OTC model, but just ask Rick how he likes it.

[LT5-Lee]

Rick, I have been thinking about it and I have a theory of what might have happened.

I do not remember the original source of the clutch problem was just the drip from the master cylinder, but I bet something just didn’t feel right so you decided to replace the slave & master cylinder and the bleeding problem began?

I theorize the lower throw out bearing ear was probable broke off when the transmission was re-installed without a jack or guide studs. Since the throw out bearing would be held tightly by the transmission nose section and with it’s thin design combined with the weight of the ZF-6, just a little excessive tail weight would been enough to not even notice it snapping off like a twig.

The depth of the notch in the bell housing is defiantly why the slave cylinder was being stopped, but it might have been created when the transmission was removed, re-installed or by the slave cylinder rod itself, who knows?

The throw out bearing is held straight by the transmission input nose, but once the ear was broke off, the fork had to twist under pressure and since the slave cylinder is extended out too far and pushing it non-concentrically, it shaves more and more into the soft aluminum bell housing until the notch gets deep enough in the housing until finally the sharp back edge of the fork gets a good solid toe and bends & brakes the new slave cylinder rod.

This also might explain the excessive shifter rattle.