IRS Axle nut questions

[Vegasjack]

Once again I am confused. Seems like constant state of confusion.
I just installed my IRS. Keeping post short, I will just say that the F5 shorter axles were installed and the spindle/hub placed on the axle.
The old axle nuts, several of them from each side, came off the old axle and fit right on the new shorter ones.
My confusion comes into play in a couple areas.
I understand the torque value of these nuts is 250#. They are a thin nut, about 1/8 inch thick. It is hard for me to comprehend trying to torque that nut, along with several others after it on same axle to 250# I have no problem buying new nuts, just have to find a source for them and that in itself seems to be difficult.
Now, my other related issue, This web site, Chelton manual and everything I read tends to say these nuts are 36mm. Mine are 1 1/4inch. My 36mm deep drive is way too big. The nut fits exactly in the 1 1/4# socket. It's a 8.8 IRS supposedly out of a 89 Tbird. Bought directly from F5, although in 2005. As said, the shorter Axles are in place and the old nuts fit nicely. What is correct Torgue and why are my nuts (lol) 1 1/4"?

Any help will be appreciated. Any known souce for better quality nuts?

Jack

[karlos]

Should be a M24-2.0 with a 36mm hex size. Dorman 615-098 is a good quality replacement. Sourced mine at Summit way back when for about $12 each. Unbelievably, when I checked Summit's website just now they show them for $46.99 each! Summit's not the only one showing that sky high price, either. Looks like these may be going the way of the dinosaur and remaining stock is becoming limited. Fortunately, Rock Auto appears to still have them at a reasonable price:

https://www.rockauto.com/en/parts/dorman,615098,spindle+nut,1616


For what it's worth, some folks had issues with these axle nuts losing torque over time. One suggested fix was to double-nut each side and torque them to the full 250 ft-lbf. That's the procedure I followed; haven't had any problems yet (knock on wood). I mention it because, as long as you're looking to buy some of these, you may want to double up on the quantity.

Good luck!

-Karl

[mike223]

The old axle nuts, several of them from each side, came off the old axle and fit right on the new shorter ones.

They are a thin nut, about 1/8 inch thick. It is hard for me to comprehend trying to torque that nut, along with several others after it on same axle to 250#

Now, my other related issue, This web site, Chelton manual and everything I read tends to say these nuts are 36mm. Mine are 1 1/4inch. My 36mm deep drive is way too big. The nut fits exactly in the 1 1/4# socket. It's a 8.8 IRS supposedly out of a 89 Tbird

What is correct Torgue and why are my nuts (lol) 1 1/4"?

Any known souce for better quality nuts?



Jack,

You're missing part of your nut.

The thin nuts (lamination) are held together by a cage which increases the O.D. of the nut(s) to 36mm.

They are designed as a one time use nut, and you certainly can't use them again without the cage.

In later years FFR sent out the Dorman nuts mentioned above - not sure why everyone wants $47 for them now, but I found one source on ebay cheap linked below.


The torque is 250ftlbs, but the driver's side has a tendency to work loose if you don't use a hardened washer under the nut.


Original nuts with cage (scroll down page): https://www.tbscshop.com/1989-1998-thunderbird-cougar-mark-viii-2003-2004-cobra-axle-shaft-nut/


Dorman replacement on ebay ($7.89): https://www.ebay.com/itm/Spindle-Nut-Boxed-Front-Dorman-615-098/181810896788?epid=169531592&hash=item2a54c61f94:g:xR0AAOSwMudbl1xd:sc:USPSFirs tClass!37921!US!-1

[Vegasjack]

Thanks Karlos! I have ordered some from rockauto. I will double nut them as well. This build seems to have an issue that I cannot get anything totally done as I am always needing to order something else to complete the job. Not a big deal, except I like to complete the job and move on. Any ways, thanks for the help.