Drive Shaft to Pinion Flange Bolts

[BadAsp427]

Trying to install the drive shaft today. Pulled the drive shaft out of the box, there are 4 bolts with it. They are 12mm / 12 point bolts with loctite all ready on them. The problem is that the holes in the drive shaft flange are only about 10mm. Also, the threaded holes in the pinion flange seem to also be about 10mm or so. Does anyone know the correct bolt for this flange? I'm at a loss as to why FF sent 12mm bolts that do not even come close to fitting into the flange. I did a search online and see that the 2015 mustang flange bolts are suppose to be 12mm. This is baffeling and I'm concerned that the 10mm +/- size bole is not as strong as the 12mm and their ability to handle the HP... Thought???

The photo below shows the 12mm on the right and a bolt that I found that seems to have a thread that is close, but when it is threaded into the pinion flange, it seems a bit loose, just not right has some "wobble". It seems to be a 3/8" course thread bolt and what I think I really need is a 10mm course thread... 10mm is just a slight bit larger than 3/8" and that would tighten up the "wobble" I'm talking about...

IMG_2187.jpg

[BadAsp427]

So a little further research I have found that the bolt size is a M10 X 1.5 and approximately 19 mm long or 3/4 of an inch. I have no idea what application this goes to because a 2015 Mustang at all the auto parts stores and online searches show that it’s a 12 mm bolt, which I have. I really wish I knew what FF sent me. And I guess they’re actually grade 12 bolts, so even if I could find this size in a grade 8 I don’t think I would trust it with 425 hp. I’m not even sure if I trust M10 with 425 hp

[mike223]

The shorter 12 point bolts are very standard (metric) Ford pinion bolts, fitting pretty much everything 1990s Ford RWD.

I don't know about the late model (2010+) Ford stuff - but I definitely recognize the 12 point bolts as being correct for 1990s Ford RWDs.

[BadAsp427]

The shorter 12 point bolts are very standard (metric) Ford pinion bolts, fitting pretty much everything 1990s Ford RWD.

I don't know about the late model (2010+) Ford stuff - but I definitely recognize the 12 point bolts as being correct for 1990s Ford RWDs.

Yes, that is correct, but not for what FF sent me... This is really strange... the 12 point bolts I have and that every ford takes is a 12mm bolt. I need the M10 it is much smaller and I'm afraid it is not the right thing for a cobra, 427 ft/lb of torque going into 315/30 size tires... I'm worried they will shear off. They are almost 1/2 the size of the 12mm bolt. Just not making sense.

[mike223]

So what pinion are you bolting to?

I think that is the key question at this point.

[rich grsc]

There is no way you're going to shear off 4 10mm bolts. Unless you forget to tighten them.

[BadAsp427]

Ok problem solved... I was originally sent the wrong pinion adapter flange for my 2015 IRS pinion. I was also sent a drive shaft for my transmission/engine combo... That drive shaft came with the 4 - 12mm bolts that I figured was for that drive shaft that they came with... wrong!!! Today, I went back to the box #11 that had the incorrect flange in it and there they were, in their shinny glory... 4 10mm x 1.5 bolts just waiting to be called upon to serve the greater good...

Case Closed...