IRS CV axle nut

[JJK]

There are two different specs in the manual for tightening the CV axle nut. On p.288 (Rev 5B) is states "Use a torque wrench to torque to 133Nm (98 lb-ft) then rotate the nut an additional 45 degrees." But, on p.328 it states to "Torque the rear axle nuts to 175 lb-ft." Which, if either, is correct? I have separately read on the forums to tighten to 250 ft-lbs.

Looking through the discussion posts, there seems to have previously been an issue with these nuts loosening over time. Is that still the case?

Thanks
JJ

[Indy Shu]

The front hubs are 225-250.
The newer spec for the CV nuts are the 98 lb-ft +45 deg

[Hoooper]

The nuts dont loosen over time, the hubs do when driven hard. Tightening them further has become a standard among track drivers, and it seems to work or at least it takes much longer to ruin a hub. And yeah the 98+45 is the Ford spec for those. The unofficial, track car spec is 150 ft-lbs + 1/8 turn. Having actually done the 98+45 I would be surprised if the 150 + 1/8 is actually more torque than the 98+45, but I am going to check when I torque mine this time around.

[phileas_fogg]

I believe the 250 ft-lbs spec is for the old Thunderbird IRS. I have no experience with the newer IRS, but the 98 ft-lbs + 45* seems like it is consistent with what I've read about the 2015 Mustang IRS.

The Thunderbird IRS nuts do in fact loosen over time. https://thefactoryfiveforum.com/showthread.php?36251-Check-your-IRS-axle-nuts!

I have not read or heard about the new IRS nuts loosening, and would be very surprised to hear they did (absent any extraordinary forces being applied).


John

[JJK]

Thank you all

[Hoooper]

Update on this. I was being dumb when I said I was going to check to see if 150+1/8 turn was more than 98+45 degrees. 1/8th turn is 45 degrees so obviously 150+45 degrees is more torque than 98+45 degrees. It comes out to maybe an extra 10-15 degrees or so. The torque on these nuts is already extremely high to get the 45 extra degrees on it, like 450ft/lbs.