trans support bolt thread?

Post by: **tedtaylor** » Wed Dec 06, 2017 1:11 am

S3 Elan transmission rear support bracket mounts to chassis frame with 4 bolts, but I can't figure out what thread size. They are NOT fine, but a course thread. I think they are neither metric or SAE, possibly "wentworth"? or whatever???
I ended up using 5/16 course thread and forcing it to work.
any direction here fellas?
thanks

Post by: **shaun** » Wed Dec 06, 2017 5:08 am

Mine are 5/16 unf

Post by: **elanman999** » Wed Dec 06, 2017 10:22 am

As Shaun says.

Post by: **tedtaylor** » Wed Dec 06, 2017 12:50 pm

shaun wrote:Mine are 5/16 unf

the receiving threads look UNC to me, so they are now 5/16 unc.
oh well.... :oops:

Post by: **elancoupe** » Wed Dec 06, 2017 2:34 pm

Ted, just keep in mind that you may not be the first person to work on that support. Thus the term DPO.

Post by: **CBUEB1771** » Wed Dec 06, 2017 5:59 pm

tedtaylor wrote:the receiving threads look UNC to me, so they are now 5/16 unc.
oh well....

The weld nuts on the chassis certainly started life as 5/16-24. If they have "evolved" to 5/16-18 you may want to helicoil them back to original configuration. They wan't hold a bolt, either UNF or UNC, very securely as they are.