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

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

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.

Click to view attachment

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

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.