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Cracked pressure plate (pic attached)


nbristow01
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Well if you have followed my threads I was having clutch issues, and knocking noise coming from under the car. Also some vibration in the tranny at certain RPMs. Well my mechanic dropped the tranny and the pressure plate has a huge crack in it. The plate has only 3000 miles on it and has been driven very tamely. These noises and vibrations started when I installed the 5 speed and new motor at the same time. So thats why we were not sure if it was the motor or tranny

Well we now know it is the tranny, pressure plate to be exact(thank goodness not the motor)

Any clue what caused the pressure plate to crack like this?

post-17424-13667633515136_thumb.jpg

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Faulty materials or poor installation...

How can a pressure plate be installed poorly? They are pretty basic I thought. Tighten the bolts down in sequence and torque to spec? I have never heard of that so thats why I am asking

You answered your own question... You'd be surprised at how little some know about basic installation concepts. I watched the owner of our local Minekie put the rim back on a 4x4 chevy truck with an impact wrench one day. He started with one lug nut and tightened it down as much as it would go with the big impact and then moved over to the one right next to it and continued in a circle until he had tightened them all down tight... Then dropped the truck off the jack and handed the customer his keys!!!

So, it is possible to install the pressure plate improperly, but it takes a real ignoramus as you pointed out.

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I still think the clue is in the bolt holes on that pressure plate. The "top" one in the picture looks fairly buggered up. I'm going with broken lock washers, or perhaps one got installed under the pressure plate, or slid down through the hole....

Check your flywheel, make sure it doesn't need resurfaced while you've got it apart, look for marks from the clutch springs, etc...

BD

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Damn, you're good...

yeah, cracking the bell is pretty impressive.

Are the straps that hold the friction surface still securely rivetted in place?

I could see the friction surface flying out and cracking the cover-

but you'd have had other symptoms long before that, I woulda thought.

I'd take it apart- carefully- to see what the rest of it looks like on the inside.

There may be more clues. The bell serves as the fulcrum for the diaphragm,

so it does take a bit of force- but not THAT much, normally.'

Maybe something got behind it and wedged? That's a long shot...

t

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To me that looks like material flaw. You should take it back where you bought it and see if they would send it to factory to be examined. A friend had same kind of issue (but different) and he got new clutch for free.

IMO that part should be rather soft steel which shouldn't develop a crack easily. It might have gotten too much heat in some manufacturing phase which made the material too hard. But I'm not a materials expert so this is just guessing.

Tommy

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whats the friction disk look like ? lets see both sides

flip the pressure plate over - what's it look like

on the friction disk side???

never saw a pressure plate crake like that in my 40 years

of nut twisting

Friction disc looks perfect, no bad spots, evenly worn. Flywheel is steel but lightened 3 lbs

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