I just acquired a set of Steeda U/D pulleys but I didn't get the hardware for it. Does anyone know what size the new crank bolt is? I take it the stock one won't work so any help I can get would be great! Oh... and I wrote Steeda but haven't gotten a response back yet.
I believe the install instructions are still on the Steeda website. The Steeda bolt is a starter bolt (if I remember correctly), and you use the stock one. Keep in mind I have read the stock ones are TTY and that is why some have failed when installing the UDPs. Some got the reusable ARP bolt.
The crank bolt is an M12 x 1.5 (I forget the length....maybe 60mm). I don't know what length the Steeda starter bolt is, but I used a 70mm and it worked perfectly. That can be a tough bolt size to find, though. I called more than a dozen bolt specialty stores here in Dallas before I found one that had it. I'm sure you could get one from Steeda, of course.
You shouldn't reuse the stock TTY (torque-to-yield) bolt because it's meant for one-time use. I'd suggest either buying a stock replacement from Ford or buying an ARP bolt (ARP 156-2501). The ARP requires a 12-point 18mm socket.