Output flange bolt, My stuff up!! |
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Output flange bolt, My stuff up!! |
DaveO90s4 |
Oct 30 2021, 05:44 AM
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#1
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Member Group: Members Posts: 149 Joined: 26-April 16 From: Australia Member No.: 19,935 Region Association: None |
Hi all. I misread the torque spec for the “drive flange expansion bolt” and over torqued it. Have now removed that bolt without it snapping. Since this bolt is really just holding the splined drive flange on, I’m inclined to think that an ‘ordinary’ M10x1.5 bolt of the oem hardness (8.8) will do the job as a replacement - unless i can get a new oem one promptly and cheaply
Any compelling views to the contrary? Thanks Dave |
Luke M |
Oct 30 2021, 05:58 AM
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#2
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Senior Member Group: Members Posts: 1,377 Joined: 8-February 05 From: WNY Member No.: 3,574 Region Association: North East States |
Hi all. I misread the torque spec for the “drive flange expansion bolt” and over torqued it. Have now removed that bolt without it snapping. Since this bolt is really just holding the splined drive flange on, I’m inclined to think that an ‘ordinary’ M10x1.5 bolt of the oem hardness (8.8) will do the job as a replacement - unless i can get a new oem one promptly and cheaply Any compelling views to the contrary? Thanks Dave Here you go. Page 25 has the torque specs. Those bolts are the expandable type and prob should not be reuse. I haven't tried to find any nos bolts so I have used old ones with no issues. http://p914-6info.net/PDFs/Group%203%20transmission.pdf |
DaveO90s4 |
Oct 30 2021, 06:30 AM
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#3
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Member Group: Members Posts: 149 Joined: 26-April 16 From: Australia Member No.: 19,935 Region Association: None |
Hi Luke thanks for your reply. Yes, i have the torque specs - just read the wrong item and overtorqued it, stopping when i felt it begin to yield. Since I felt it yield I’m very reluctant to use it again. So am thinking about options.
Any more views, opinions, suggestions etc much appreciated. Cheers Dave |
Superhawk996 |
Oct 30 2021, 07:54 AM
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#4
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914 Guru Group: Members Posts: 5,900 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
Any compelling views to the contrary? Thanks Dave I haven't tried to find any nos bolts so I have used old ones with no issues. (IMG:style_emoticons/default/agree.gif) However, I would not simply use a regular shank bolt. The OEM expansion bolt is designed to stretch a very specific amount under the prescribed torque. In addition the OEM bolt is a vastly better design than a common shank bolt. That stretch of the bolt is what keeps the flange from loosening due to cyclic torque applied to it. The OEM expansion bolt is necked down after the thread form to eliminate stress risers that can orginate from the root of the threads. I don't know what the material grade is but I'd bet it is probably closer to 10.9 rather than a 8.8 (Grade 5 SAE). In modern chassis and powertrain applications, highly stressed bolts (like an expansion bolt) would typically be 10.9. If you use a standard shank bolt, you will not get the same stretch (i.e. clamp load) from the bolt as you will with the OEM expansion bolt at the prescribed torque. Given that you have yielded your OEM expansion bolt, Do Not reuse that one. Find a used one on the forum. If you can't find one - PM me. I know I have some in storage . . . . where is a whole different question (IMG:style_emoticons/default/laugh.gif) |
914Sixer |
Oct 30 2021, 08:11 AM
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#5
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914 Guru Group: Members Posts: 8,906 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
This bolt is NLA from Porsche. However they are making replicas. Here is one from the UK on Ebay. Click to open I have one I can send you.
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