Pressure Plate Failure

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DurocShark
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Pressure Plate Failure

Post by DurocShark » Tue Sep 04, 2018 8:14 pm

I've never seen a pressure plate fail like this before. Is it common? Obviously, old one on the left, new one on the right.

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Amskeptic
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Re: Pressure Plate Failure

Post by Amskeptic » Wed Sep 05, 2018 5:56 am

DurocShark wrote:
Tue Sep 04, 2018 8:14 pm
I've never seen a pressure plate fail like this before. Is it common? Obviously, old one on the left, new one on the right.

It is commonly seen in pressure plates with those collars grafted on to the diaphragm fingers to work with the earlier transaxles. The problem is over-extension of the diaphragm spring weakens it until it finally does the "over-center of death". This is especially seen in the Brazilian pressure plate springs. You avoid over-extension by making sure that the cable adjustment is loose enough to make disengagement about two inches from the floor. You may have a lot of free play when the disk is new. If you rigidly demand the Bentley-specified 1" free play, it can allow the release bearing to push too far.

The things we have to look out for . . . .
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 91 414 miles
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Re: Pressure Plate Failure

Post by asiab3 » Wed Sep 05, 2018 8:41 am

Seen it? Yes. To that extent? No! :scratch:

What were the symptoms that prompted your investigation?

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DurocShark
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Re: Pressure Plate Failure

Post by DurocShark » Wed Sep 05, 2018 9:33 am

Clutch was slipping and chattering. Adjusting was impossible. It was either WAY too loose or too tight with one click on the wingnut. Wouldn't fully disengage if loose, and wouldn't fully engage if tight (or is it the other way around? I forget...) I was complaining about it here a couple months ago.

I'm swapping the engine anyway, that 2180 leaked like crazy. I have an 1835 I've been building that's going in there so I can tear down the 2180. I needed the hardware for the pressure plate for the new engine, so I pulled the pp off to get those screws just to see what the issue was.

It's a KEP Stage 1 plate. I'll probably replace it with another Stage 1 kit when I rebuild the 2180. That torquey little engine probably needs it. ;)

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Re: Pressure Plate Failure

Post by DurocShark » Wed Sep 05, 2018 9:34 am

Amskeptic wrote:
Wed Sep 05, 2018 5:56 am
DurocShark wrote:
Tue Sep 04, 2018 8:14 pm
I've never seen a pressure plate fail like this before. Is it common? Obviously, old one on the left, new one on the right.

It is commonly seen in pressure plates with those collars grafted on to the diaphragm fingers to work with the earlier transaxles. The problem is over-extension of the diaphragm spring weakens it until it finally does the "over-center of death". This is especially seen in the Brazilian pressure plate springs. You avoid over-extension by making sure that the cable adjustment is loose enough to make disengagement about two inches from the floor. You may have a lot of free play when the disk is new. If you rigidly demand the Bentley-specified 1" free play, it can allow the release bearing to push too far.

The things we have to look out for . . . .
Colin
This makes more sense to me than the explanation I got on TS, that the installer had incorrectly torqued the pressure plate. Thanks!

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