ARCHIVE Wits' End Nut Huggers

[NLXTACY]

Now time for something a little different...

NOTE: If your knuckle hardware is properly torqued, and not needing a rebuild, there is NO reason to take it apart just to use these. Keep your setup as is until the next rebuild.

At this point in 80 Series Land Cruiser ownership you *should* have heard the term "Check Yer Nuts". This saying refers to your axle's knuckle hardware. They are known to work loose, fall out or sheer which can lead to complete knuckle failure where the steering arm works itself off and the knuckle and tire fold inside the wheel well. It sounds extreme but it occurs way too often. Why does this happen? Is it something defective in the knuckle? The answer is NO.

The reason why they come loose is because either the knuckle wasn't properly rebuilt (simple things can be missed) or from something as simple as re-torquing the knuckle hardware. These are HEAVY DUTY trucks and require constant checking for long term use. You can't just set it and forget it, especially if you are going off pavement at all. In fact, after each off road excursion you should check the knuckle hardware. If this is the first you are hearing of this, well consider it gospel because bad things can happen.

So what do these fancy shmancy "Nut Huggers" do? Well, at minimum all it does is replace the OEM washers that makes up the hardware stack in your knuckles. At its best, when installed properly, they will prevent the knuckle hardware from falling apart and ruining parts.

When you are finally ready to rebuild your axles OR if you notice you are missing/loose hardware, then its the ideal time to utilize these in the rebuild process. You will need to:
• Completely clean and de-grease the mounting surface of the steering arm and knuckle
• Use a sanding block/file to make sure both the knuckle and steering arm surfaces are flat and smooth
• Be sure the knuckle studs are tight in the knuckle itself, the shoulder will prevent the stud from going too far
• Put the steering arm in place with the cone washers
• Place the NUT HUGGER instead of the OEM washers, DO NOT use the OEM washers
• Hand tighten the nut (with the flat edge toward the knuckle)
• Torque the nuts to 71ft lb.
• Do NOT bend the tabs yet
• Drive 500 miles and re-check the torque and verify 71ft lb
• Now go ahead and use a screw driver to bend the tabs up and then use a brass drift and hammer to knock ALL tabs into the knuckle nut to lock it's position in place

80 Series Nut Hugger- Toyota Solid Axle Knuckle

80 Series Nut Hugger- Toyota Solid Axle Knuckle (SAK-1)

absolute-wits-end.com

 

[baldilocks]

Are these real world tested??

 

[NLXTACY]

Are these real world tested??

Only reason I'm finally posting. About to throw them onto the turbo truck as well.

Keep in mind, worst case scenario, its an expensive fancy washer.

 

[baldilocks]

This type of security device is trusted in certain cases on commercial aircraft so you may be onto something with these.

 

[NLXTACY]

This type of security device is trusted in certain cases on commercial aircraft so you may be onto something with these.

honestly I started with a security wire solution but I really didn’t trust most to follow thru correctly so I went this route.

 

[slow95z]

This type of security device is trusted in certain cases on commercial aircraft so you may be onto something with these.

its also trusted about 3 inches away to keep your wheel from falling off at the bearing

 

[baldilocks]

its also trusted about 3 inches away to keep your wheel from falling off at the bearing

I think I will continue with regular torque checks. This has always worked for me and removes all doubt.

 

[slow95z]

I think I will continue with regular torque checks. This has always worked for me and removes all doubt.

I am on the other end of the spectrum, I give em a few uggaduggas and ride but then I am never that far from home in mine.

 

[baldilocks]

I am on the other end of the spectrum, I give em a few uggaduggas and ride but then I am never that far from home in mine.

In fact, I have, in waiting to be installed with my next tear down, a set of high strength knuckle studs/nuts made by ARP exclusively for Front Range off-road that get torqued to 120lb.ft creating substantially more clamping force.

 

[slow95z]

In fact, I have, in waiting to be installed with my next tear down, a set of high strength knuckle studs/nuts made by ARP exclusively for Front Range off-road that get torqued to 120lb.ft creating substantially more clamping force.

So 3 uggaduggas right?

 

[Outsane]

I am going to call the nut huggers ,

banana hammocks

And add to my next order

Thanks

 

[patrickk]

Added to my wish list, which is getting pretty damn long.

 

[Cruzilla]

We use the same kind of fastener security in the military and I have used them on my personal vehicles in the past.
They work great for the most part, my only concern would be for the stretch factor on a fastener under load or torque.
If the fastener stretches and it loses it applied torque you will loose its load bearing ability. Once that happens it will likely shear when under high load or stress.
I would use these, but would still check your torque values from time to time.

 

[OffRoadScott]

Another great idea.

 

[nukegoat]

Once you lose tension, can't the stud just back out, especially given the asymmetric threading? I thought these sort of retention devices only applied to bolts in tapped holes or nuts on fixed threads.

 

[Rwhat]

I guess I’m not the only one to think Joey was coming out with a line of European men’s swim wear.

 

[NLXTACY]

Once you lose tension, can't the stud just back out, especially given the asymmetric threading? I thought these sort of retention devices only applied to bolts in tapped holes or nuts on fixed threads.

huh? The nut cant turn and the stud cant thread through the nut because of the shoulder

 

[nukegoat]

huh? The nut cant turn and the stud cant thread through the nut because of the shoulder

How many threads are between the shoulder and the edge of the nut with these?

Then
if (((num threads / coarse tpi) - (num threads / fine tpi)) > nuthugger.tangheight)
You.fail();

 

[NLXTACY]

How many threads are between the shoulder and the edge of the nut with these?

Then
if (((num threads / coarse tpi) - (num threads / fine tpi)) > nuthugger.tangheight)
You.fail();

Matt why in the fawk do you force me to waste time with your silly formula? Do you feel the need to troll everything?

The difference in pitch on each end of the stud is what makes this solution work so well. The stud has a 1.5mm pitch on the knuckle side and 1.25mm pitch on the nut side. This means the stud will move linearly 1.5mm in one turn while the nut only moves 1.25mm linearly with one turn.

If the stud is able to back out the threads will become mechanically bound because of the pitch difference. The nut can’t rotate and the stud can’t push the nut away from the joint without bending the .075” thick Nut Hugger. .075” of steel that spans 2.36” center to center is surprising strong and a stud backing out from vibration isn’t going to bend it.

For the formula you posted (which actually doesn’t work because of the difference in pitch) lets assume same that the stud is the same pitch on each side and the "fail" scenario you mentioned is able to happen. The ears of the Nut Hugger extend about .37” up the side of the nut. The shoulder of the stud would contact the nut after moving .23” and then stop rotating. The stud would still have about 5 threads of engagement into the knuckle and the nut would still be fixed from rotating by the Nut Hugger. The stud would not fall out but obviously this stud would not be contributing to the clamping force anymore but just be able to handle a little single shear load. Like I mentioned this scenario won’t happen because of the different pitch on each end of the stud.

As you so eloquently put it in another thread, leave the engineering to the engineers.

 

[nukegoat]

Matt why in the fawk do you force me to waste time with your silly formula? Do you feel the need to troll everything?

The difference in pitch on each end of the stud is what makes this solution work so well. The stud has a 1.5mm pitch on the knuckle side and 1.25mm pitch on the nut side. This means the stud will move linearly 1.5mm in one turn while the nut only moves 1.25mm linearly with one turn.

If the stud is able to back out the threads will become mechanically bound because of the pitch difference. The nut can’t rotate and the stud can’t push the nut away from the joint without bending the .075” thick Nut Hugger. .075” of steel that spans 2.36” center to center is surprising strong and a stud backing out from vibration isn’t going to bend it.

For the formula you posted (which actually doesn’t work because of the difference in pitch) lets assume same that the stud is the same pitch on each side and the "fail" scenario you mentioned is able to happen. The ears of the Nut Hugger extend about .37” up the side of the nut. The shoulder of the stud would contact the nut after moving .23” and then stop rotating. The stud would still have about 5 threads of engagement into the knuckle and the nut would still be fixed from rotating by the Nut Hugger. The stud would not fall out but obviously this stud would not be contributing to the clamping force anymore but just be able to handle a little single shear load. Like I mentioned this scenario won’t happen because of the different pitch on each end of the stud.

As you so eloquently put it in another thread, leave the engineering to the engineers.

I don't think it mechanically binds. The fine thread would have to be in the knuckle. You have it backward