ARP hub studs failure (1 Viewer)

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Update. We have 100% confirmed with both Trail Gear and more importantly ARP (Automotive Racing Products) that these are indeed manufactured by them for Trail Gear. Same spec material as their black ones with the hex head and cad plating per TG's spec. We took a few (4) of the undamaged ones we we received back and were able to measure them (length) before and after we installed, torqued and re-installed on a wheel hub using an AISIN hub up at the old shop. They pulled tight and torqued to spec both times without any new elongation (I need to measure new ones at the shop). Obviously there are some that did in fact strip so we can't do anything to test those. ARP said they can/do have a rare thread issues with some bolts/studs in a large batches so it's entirely possible this was just crappy luck that Gleb ended up with them :( I plan to do a little write-up on the new vs used vs multiple re-torques on both the OEM Toyota and TG ARP studs, I need to do the stock ones next and use a drive flange to see if thickness of the flange has any impact.

There were many suspect that these were built by ARP (myself included after hearing some had stripped) and after chatting with Gleb today on his refund, I wanted to quickly chime in and at least update that ARP owns that they make em. Now, I'm almost wondering if the nuts could potentially be the issue. ARP doesn't provide those and TG didn't immediately have any specs on those. It would be dumb for those to damage the stud threads but... ?? I'll add OE nuts versus aftermarket nuts to my test. Fortunately this is/was an isolated issue.
 
Yeah, good follow up, great to put a . on this !
 
Bringing this recent thread to the top.

I just finished the Rubicon Trail last week in my 80. Before the trip I had RCV axles installed and my knuckles rebuilt with ARP knuckle studs. After climbing Cadillac Hill, the trail turns into a single track dirt road for a bit. As I continued on the trail, I noticed my last two steering inputs did not do anything. I got out of the truck to look and found the tires pigeon toed and found all four passenger side studs a few feet back. Grease and gear oil were pouring out, the wheel had almost come off. The studs had ripped the threads out of the knuckle.

Thankfully, some Jeeps stopped and helped me cobble together a trail fix. We cleaned up the threads, put the bolts back in the knuckle, put a plate from a hi-lift underneath them, and rachet strapped it together. It actually worked for about 400m before failing. At that point we decided to camp. The next day we met up with our friends who were a little further back on the trail. They began climbing CH and we bumped into @gifu (THANK YOU AGAIN!) who happened to have an 80 PS knuckle. When we got back to my truck, we pulled the knuckle, replaced and rebuilt it. I was able to get all the way back to NJ with this fix.

Before I attempt to repair this, I would like to better understand the failure. Planning to replace knuckle (currently using non-ABS knuckle), rebuild knuckle, and replace gear oil. There were three other 80's with me that drove cross country, did the same trail, and recently had their knuckles rebuilt. I am not sure what caused it and want to implement a fix that addresses the issue for good. Attached is a picture of the studs.

Any insights?

IMG_7496.jpg
 
@JZelnick small note, my original post was in regards to ARP hub studs (x6 per wheel), which are not the same as the knuckle studs (4x per knuckle). Just saying they are a different part.

Glad you were able to trail fix your rig and make it out of there! Holy cow what a crazy adventure.
 
Just to confirm, is that exactly how you found the hardware?

Yes this is exactly how they fell out of my truck. Can someone confirm that the long end of the Front Range ARP knuckle studs should go inside the knuckle? I understand that is how OEM is installed, but want to ensure that is the case for the FR ARP knuckle studs.

ARPs have no tooling end for install? Are those nylock nuts? 😳

ARP noted this when i just called their tech support. They said those are not ARP studs (ARP should be printed on them). They also noted their should be an allen key hole for install. I don't know how Front Range sources these studs, but they are part of a kit and include the nuts.


@JZelnick small note, my original post was in regards to ARP hub studs (x6 per wheel), which are not the same as the knuckle studs (4x per knuckle). Just saying they are a different part.

Glad you were able to trail fix your rig and make it out of there! Holy cow what a crazy adventure.

Thank you for clarifying, that is my mistake.
 
Bringing this recent thread to the top.

I just finished the Rubicon Trail last week in my 80. Before the trip I had RCV axles installed and my knuckles rebuilt with ARP knuckle studs. After climbing Cadillac Hill, the trail turns into a single track dirt road for a bit. As I continued on the trail, I noticed my last two steering inputs did not do anything. I got out of the truck to look and found the tires pigeon toed and found all four passenger side studs a few feet back. Grease and gear oil were pouring out, the wheel had almost come off. The studs had ripped the threads out of the knuckle.

Thankfully, some Jeeps stopped and helped me cobble together a trail fix. We cleaned up the threads, put the bolts back in the knuckle, put a plate from a hi-lift underneath them, and rachet strapped it together. It actually worked for about 400m before failing. At that point we decided to camp. The next day we met up with our friends who were a little further back on the trail. They began climbing CH and we bumped into @gifu (THANK YOU AGAIN!) who happened to have an 80 PS knuckle. When we got back to my truck, we pulled the knuckle, replaced and rebuilt it. I was able to get all the way back to NJ with this fix.

Before I attempt to repair this, I would like to better understand the failure. Planning to replace knuckle (currently using non-ABS knuckle), rebuild knuckle, and replace gear oil. There were three other 80's with me that drove cross country, did the same trail, and recently had their knuckles rebuilt. I am not sure what caused it and want to implement a fix that addresses the issue for good. Attached is a picture of the studs.

Any insights?

View attachment 2393653


Based on the comment on page one that "the long side goes into the hub" were these installed short side in the hub? Normally the locking cones on trucks have no or 1 washer. My experience in mainly on big trucks.
 
Nylocks- brilliant! So a significant amount of the force applied goes towards moving the nylon over the threads. Who needs clamping force?
 
Something does not look right, really strange that they all fell out at the same time. Hears a pik of my ARP knuckle studs you can see they are gold in color and still look new after two years on the Reg. By the way I check my nuts after every day of hard wheeling.
1596574038926.png
 
The studs couldn't have been put in backward, since the thread pitch is different on each side.

The studs didn't *fail*, so I'd put the blame on the recent rebuild. And/or failure to check/retorque after the initial installation? My 27 year old stock studs are always tight, every time I check them. Have never come loose. My frequency of checking has gotten pretty lax because of that. (but it's still a good idea to check periodically)
 
@-Spike- These are not Nylocks. They are " 8 class 10 all metal locking nuts " according to the Front Range ARP product page.

The studs couldn't have been put in backward, since the thread pitch is different on each side.

The studs didn't *fail*, so I'd put the blame on the recent rebuild. And/or failure to check/retorque after the initial installation? My 27 year old stock studs are always tight, every time I check them. Have never come loose. My frequency of checking has gotten pretty lax because of that. (but it's still a good idea to check periodically)

You are correct. The thread pitch is different and they could not have been put in backwards. The course (short) side goes in the knuckle and the nut goes on the fine side (long side) on the Front Range ARPs. It's odd why the orientation is swapped from OEM (long side in the knuckle). These ARP's get torqued to higher then OEM spec so I don't know how they could have gotten loose so quickly after initial install.

Here are some pictures of the bottom of the knuckle. You will note one side has some visible damage around the threads.

Any thoughts?

IMG_7498.jpg


IMG_7499.jpg


IMG_7500.jpg
 
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The usual mode of failure is for the fasteners to get loose, allowing the assembly parts to move independently, putting side/shear loads on the fasteners, damaging the parts. That's what looks like happened here, but that's just an (educated) guess.

Failures like this are almost always due to faulty installation, in my experience. You have aftermarket parts with non-OEM-specced fasteners, so that adds some confusion. No matter what type of friction-locking nuts those are, they will require more torque to attain the same clamping force on the assembly. Did the supplier specify a higher torque value? Was it appropriate? Then there's the usual questions- were the parts clean, mating surfaces flat, did they seat properly, were the threads in good condition, were proper procedures followed, etc.
 
This was the link the installer provided for how they installed them. It seemed to address most of your points (higher - 110 ftlb torque spec, cleaning hardware, etc). Certainly can't speak to everything, but seemed like they had the right idea.
 
The usual mode of failure is for the fasteners to get loose, allowing the assembly parts to move independently, putting side/shear loads on the fasteners, damaging the parts. That's what looks like happened here, but that's just an (educated) guess.

Failures like this are almost always due to faulty installation, in my experience. You have aftermarket parts with non-OEM-specced fasteners, so that adds some confusion. No matter what type of friction-locking nuts those are, they will require more torque to attain the same clamping force on the assembly. Did the supplier specify a higher torque value? Was it appropriate? Then there's the usual questions- were the parts clean, mating surfaces flat, did they seat properly, were the threads in good condition, were proper procedures followed, etc.
Torque spec per Front Range Off Road is 110-120lbft. The run on torque of the nuts is insignificant when compared to the possible increase of 50lbft of torque and the subsequent increase in clamping force.

His studs were improperly installed. I’ve ran Rubicon at least 50 times in various Toyota’s and one old Dodge and not once did I have hub or knuckle stud failures. It’s all about torquing ur nuts and lubing ur shafts regularly.
 
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Something does not look right, really strange that they all fell out at the same time. Hears a pik of my ARP knuckle studs you can see they are gold in color and still look new after two years on the Reg. By the way I check my nuts after every day of hard wheeling.View attachment 2393706
Which nuts and washers are you using? Also where did you purchase the ARP knuckle studs? Everywhere I checked they only sell the studs separately without the nuts. Thanks a lot!
 
Which nuts and washers are you using? Also where did you purchase the ARP knuckle studs? Everywhere I checked they only sell the studs separately without the nuts. Thanks a lot!
Honestly, it's been over 5 years and I can't remember :rolleyes:
 

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