Spindle Nut Installation and Torque

[drunkonunleaded]

I’m in the process of installing a pair of new FRPP hubs with ARP studs. Right side went on without a hitch. I hang tightened with a standard 1/2” socket wrench and send them home to 249.5 lb. ft. with my digital torque wrench. No issues there.

The left side was the complete opposite. I was diligent in cleaning the threads after removing the original hub. This time around, the nut could barely do a few turns before becoming very difficult to turn. By the time the spindle was flush with the end of the nut, it was taking over 150 lb. ft. to even move.

I was paranoid about crossthreading the spindle, so I backed the nut off and checked the threads. The spindle threads look fine. I tried the old nut for good measure. Went about two turns, met a little resistance, but freed up. Again, I could install this with a standard socket wrench to snug.

So I ordered up a pack of four nuts from the local Ford dealer for pickup tomorrow. In the meantime, I tried the new nut again. It went farther but again met resistance eventually.

I backed off once again and tried a drop or two of oil on the threads. This time it went almost to snug by hand.

It appears as though the red compound these. It’s is causing a lot of resistance. So much so that the nut and spindle were getting warm to the touch when tightening. Is this a common occurrence? Did I just draw a short straw with regards to tolerances?

I’m hoping a new nut is the ticket here because even getting these tightened to halfway forced me to break out the 24” ratchet. Even that had a bit of a hard time.

 

[JAJ]

I’m in the process of installing a pair of new FRPP hubs with ARP studs. Right side went on without a hitch. I hang tightened with a standard 1/2” socket wrench and send them home to 249.5 lb. ft. with my digital torque wrench. No issues there.

The left side was the complete opposite. I was diligent in cleaning the threads after removing the original hub. This time around, the nut could barely do a few turns before becoming very difficult to turn. By the time the spindle was flush with the end of the nut, it was taking over 150 lb. ft. to even move.

I was paranoid about crossthreading the spindle, so I backed the nut off and checked the threads. The spindle threads look fine. I tried the old nut for good measure. Went about two turns, met a little resistance, but freed up. Again, I could install this with a standard socket wrench to snug.

So I ordered up a pack of four nuts from the local Ford dealer for pickup tomorrow. In the meantime, I tried the new nut again. It went farther but again met resistance eventually.

I backed off once again and tried a drop or two of oil on the threads. This time it went almost to snug by hand.

It appears as though the red compound these. It’s is causing a lot of resistance. So much so that the nut and spindle were getting warm to the touch when tightening. Is this a common occurrence? Did I just draw a short straw with regards to tolerances?

I’m hoping a new nut is the ticket here because even getting these tightened to halfway forced me to break out the 24” ratchet. Even that had a bit of a hard time.

View attachment 111677

I'm going to start my reply with a question... why are you torquing to 150ft-lbs?

The Ford Maintenance Manual for S550 Mustang that I have says:

1. NOTE: Apply the brake to keep the halfshaft from rotating.
   Install the new spindle nut.
   Torque :
   Stage 1: 98 lb.ft (133 Nm)
   Stage 2: 45°

Now, on my GT350, that "45 degrees" leads to a finished torque of around 400 ft-lbs. I use a 3' pipe extension on my 20" tee handle.

The key point is that if you tighten to 150 ft-lbs, there's a very real possibility that it'll come loose at some point. There've been lots of threads on this problem.

The second point is the goop on the nut. It's a special kind of thread locker that starts out soft so it deforms when it's being done up and then it hardens and locks after you're done. If it's damaged, you should get a new nut and start over. That said, I didn't use those nuts when I did mine - I reused the factory nuts - and they've been fine since 2018 or so and a bunch of track time. Just put a witness mark on the finished assembly so you can see if the nut is coming loose.

 

[665.0coupe]

I'm going to start my reply with a question... why are you torquing to 150ft-lbs?

The key point is that if you tighten to 150 ft-lbs, there's a very real possibility that it'll come loose at some point. There've been lots of threads on this problem.

He's not torquing it to 150ft-lbs. He's saying that it takes 150ft-lbs of torque to thread the nut on the spindle. This is before it is threaded on far enough to start the torque sequence.

 

[drunkonunleaded]

He's not torquing it to 150ft-lbs. He's saying that it takes 150ft-lbs of torque to thread the nut on the spindle. This is before it is threaded on far enough to start the torque sequence.

Thank you. Yes, the concern was that I had to put 150# if torque on to just thread the nut on past a few threads. The other side went snug by hand. I get that not many are using digital torque wrenches so that might’ve been confusing.

For future reference: It was the nut. I purchased a second new nut from the dealership this morning and it went on by hand with no issue. Torqued to 249.4.

Lesson learned: Keep spare nuts on hand.

I’m annoyed that there was some sort of issue with a brand new nut, but I’m happy it was not the spindle.

Both nuts are torqued to 249.4 and 249.5, respectively and I’ve marked their position with tamper detection paste.