Explain to me how a bad flywheel can ruin a pressure plate

[GoFaster]

I got the clutch done in my tundra about 10k miles ago. I went to my hometown to get this done with my local family mechanic. As soon as I got back home I noticed I still had heavy clutch chatter and the mechanic admitted that he didn't refinish the flywheel. I didn't mind the chatter bad enough to take a weekday off and drive back there so I went with it.

It started getting hard to shift so I was slowly extending the push rod to get more throw. I finally took it to a shop in town today and I found out that my pressure plate is missing 5 fingers. Only two of them are able to be found. So now, only 18 months after I pad almost 700 to my local family friends shop, I am paying another 700 to have everything done again.

I want to ***** at the first mechanic but I can't exactly explain how the bad flywheel could ruin it. Can someone explain it to me so I can explain it to him?

[kovawa]

I think the only thing you could explain is this- Pressure plates and clutch discs live longer happier lives when they're mated to newly machined flat surfaces. Mounting new clutch parts to a worn and possibly warped flywheel is never a good idea. A warped flywheel will cause the pressure plate "fingers" to sit at differing elevations in relation to the throw out bearing. Because of this condition- The throw out bearing will contact and load each finger differing amounts, resulting in the eventual failure of the fingers with the highest load.
That's my $.02 - I used to work as a tech, and I can remember that I would sometimes have to wait days for a replacement flywheel to come in to the shop, before I could complete a clutch job. Sometimes the delay was due parts unavailability or a lazy machinist at the local machine shop. Either way- no clutch job ever left the shop without a new or freshly machined flywheel.

[Sportsmanphil]

Its also possible that while putting the trans back in place the input shaft was jammed into the pressure plate fingers causing damage.

[TheGryme]

I don't think it can........did the original mechanic change the throw out bearing and fork or whatever mechanism is in there too?
Maybe it was the wrong pressure plate or a cheap re-man?
He could've bent the fingers when he was reinstalling the trans....is it a 4x4? That make a differeance in the weight and hassle factor of putting it all back in cleanly.
Even not having the right tools can screw things up.

Sorry....I wish I could offer more info.

[kovawa]

The Op got 10k out of the clutch. Chances are- any damage that could have been caused when reinstalling the tranny would have shown up long before the 10k mark. Then again- if the mechanic was unwilling to use a new/reman flywheel during the install, maybe he cheaped out on the quality of the rest of the parts used. It's all Monday morning Quarterbacking from here on out.

[Sportsmanphil]

I seriously doubt a warped flywheel caused this IMO. A warped flywheel is shaved, removing material measured in the thousands. The pressure plate fingers operate independently and is separated by the friction plate which isnt as rigid as steel and therefore is forgiving.

In addition, the old pressure plate operated without this kind of damage on the same warped flywheel.

Extending the pushrod may have over extended the throw of the pressure plate, which can bend the fingers; but this is speculation only.

You could have operated missing a few fingers and not noticed, but the added stress over the last 10K would eventually cause more to break until you did notice. That said, there is no telling when the fingers started to come off, they may not have all broke recently.

Question: what condition was the clutch disk in?

[Jonesy]

I had an experience with replacing my own clutch several years ago ~ something I'd like to forget. My clutch was worn out and I consulted a mechanic friend who has years of experience with this sort of thing. He suggested buying remanufactured parts from a local supplier and having them resurface the flywheel at the same time which I did.
In a mater of months the thing was chattering to beat the band and only got worse. It was a bad decision on my part.
Another mechanic suggested using nothing but new parts ~ he never wants to do the same job twice so he's a firm believer in not using remanufactured parts on a job like this. I learned my lesson the hard way. I never did find out what went wrong with that vehicle as I sold it quickly and bought the new/used Tundra that I'm currently enjoying.
And so it goes . . .