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Fly Wheel Bolt Grade?

 
Old 05-17-2005, 09:03 PM
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Default Fly Wheel Bolt Grade?

Hi everyone I am just getting ready to commence on the clutch job and I was wondering if someone knew the grade of bolts used to hold the fly wheel to the crank?. I was told that the heads strip when taking them off.


Regards Dan 1990 928 GT
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Old 05-17-2005, 11:55 PM
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Originally Posted by pasa
Hi everyone I am just getting ready to commence on the clutch job and I was wondering if someone knew the grade of bolts used to hold the fly wheel to the crank?. I was told that the heads strip when taking them off.


Regards Dan 1990 928 GT
Some of the heads might strip, but if you get the triple-square socket in all the way and it is straight you probably won't strip any. On mine, I ended up messing up one bolt but I had three on hand just in case so I didn't have to wait for them to ship if I messed up. The local dealers don't keep them in stock. You should use the original bolts available at the Big 3 since they are the correct size and, more importantly, weight. You don't want a flywheel that's off balance because of a bigger head on a different bolt.

Part number is 928 102 151 01 for the flywheel bolt.

Here's a thread where several folks had great suggestions for getting the flywheel bolts off safely: https://rennlist.com/forums/showthre...ferrerid=27688

Here's a write-up on the RMS replacement by Bill: http://www.billsworkshop.com/P928S4/seal/seal.htm
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Old 05-18-2005, 12:59 AM
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I just replaced the rear crank seal on Saturday. The 12mm triple square-headed socket attachment took them off easily. I sprayed them all with PB Blaster before removing them to loosen up any corrosion.

Putting them back on was easy, too. The crank fitting has a location pin on it so you can't re-attach the flywheel wrong. Just go slow and be careful as you torque them down.
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Old 05-18-2005, 01:15 AM
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outta curiosity, why would weight for the bolts matter? Aren't they evenly spaced to distribute the weight?
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Old 05-18-2005, 01:41 AM
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Originally Posted by mspiegle
outta curiosity, why would weight for the bolts matter? Aren't they evenly spaced to distribute the weight?
They're evenly spaced but at the rate they're spinning a weight difference could cause some vibration. Kind of like a tire. Even though the wheel and tire are evenly distributed, if the weight is off on one end by a little bit, the tire shakes.
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Old 05-18-2005, 11:37 AM
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Hi John

Thanks for the info. If I were to strip a bolt I would replace all the bolts as I hate reusing old rusty bolts. I just can't wait for the replacements to arrive on the slow boat to China. I have a great source for fasteners I just need to know the grade of bolts. Any help would be greatly appreciated .

Regards
Dan 1990 928GT
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Old 05-18-2005, 12:12 PM
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Originally Posted by pasa
Hi John

Thanks for the info. If I were to strip a bolt I would replace all the bolts as I hate reusing old rusty bolts. I just can't wait for the replacements to arrive on the slow boat to China. I have a great source for fasteners I just need to know the grade of bolts. Any help would be greatly appreciated .

Regards
Dan 1990 928GT
You'll probably have to ask one of the guys at the Big 3 about the actual grade.

If you follow those suggestions on that thread I referenced (read the whole thing before you start) you probably won't strip any. The key is to get the tripple-square socket in all the way and have it as short as possible so it doesn't angle down when you try to turn it. The one I stripped was before I asked anything so I really didn't know what I was doing. Use the PB blaster as Big Dave suggested and you should be ok. Spray your flywheel bolts as soon as you get the clutch assembly out and let them soak while you're rebuilding your clutch.

Most important, before you do something trying to "figure it all out" on your own, ask for suggestions even if you think it's a stupid question. It'll save you hours of headaches and keep you from letting some words fly that you really didn't want to say. Ask me how I know this.
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Old 05-18-2005, 04:36 PM
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Thanks John


Regards Dan 1990 928 Gt
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