knuckle stud thread

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timmbuck2

timmbuck2

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I don't want to keep the "stuck in grand junction" thread going, don't want the thread title to worry anyone.
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I want to try and figure out what is happening here, other than neglect by me in checking this on my rig after wheeling trips and before long trips.

(FYI...if you did not see my earlier thread, last Saturday night in Grand Junction Colorado I was going around a corner downtown at 5mph when my steering arm FELL OFF. Apparently 3 of my passenger side knuckle studs had fallen out and the last one sheared off going around the corner. I had it towed to Safari where Hugh found that 2 knuckle studs were also missing on the drivers side)

About a 18 months ago at the 2008 rising sun wheel bearing packing party I did a complete front axle job on my 80 (I did not replace any bearings or take apart my birfs) I was late and definitely had to hurry through the 2nd half. (Please note I am NOT looking for blame or pointing fingers at ANYONE but myself. I had great mentors at the WBPP and I take 100% responsibility for any wrenching I did on my rig) Everything seemed great, then about 6 months or so later I noticed my steering was getting loose, then found a huge pile of grease/gear oil under my pass. front tire one morning. 3 of the knuckle studs were very loose, I think one was gone completely. Steering was very loose due to the steering arm being so loose. So I did another complete axle job to the pass. side, but this time I did do the trunion bearing. I put in all new studs, did not locktite them. I checked both sides at the next oil change a month or so later, and everything was fine.

Fast forward to this past weekend. With no symptoms at all, I had been driving around with only 1 stud on the passenger side and 2 on the drivers side.
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I did not check them at the last oil change. The rig is sitting at Safari Ltd. in Grand Junction with a $1500 bill to do the whole front end again, new wheel bearings and trunion bearings (said the races are toast on the pass. side, the ones with less than 12k miles on them) and everything.

My main question is how are these studs working free? What would cause this? It seems like it happens after a axle job, but what could I do to the knuckle to make these studs work themselves free?? Hugh mentions among other things the bearing preload, which at the WBPP we used the fish scale for, but when I re-did the pass. side I did it by feel.

I do take complete responsibility for not checking them and this is now going to be a regular maintenance item, but I am just trying to understand how and why it happens, and maybe prevent it from happening again on my rig or to someone else. I also am not completely convinced that my driver's side needs to be completely re-done.

Anyway, thanks for reading, and if you have an 80 PLEASE go check your knuckle studs!
 
This typically happens at some point after a steering arm is removed. The knuckle studs tend to loosen when the nuts are removed and the studs need to be properly reinstalled in the knuckle every time a steering arm is removed.

The main reason the RH side is more likely to come loose is because the RH steering arm is being pushed and pulled by both the drag link and the tie rod and is getting wiggled from the front and the back. My bet is the LH side comes loose on RHD trucks.
 
Were the studs replaced with the newer style that have a E12 Torx head on the end?
I have a 96 in the garage right now getting a front axle rebuild and noticed last night the earlier style studs were loose. I think one of the keys here is making sure the threaded holes in the knuckle are clean and free of grease when you initially install the studs. I have made it a practice to clean the knuckles in solvent, chase the holes with a tap, and apply locktite to the new studs which are torqued to about 50 ft lbs. I have yet to have the newer style studs back out. Loctite will seal the threads and prevent grease from working its way in. Also, though not proven, I suspect the cone washers can wear over time. I usually wont hesitate to replace these as well.
 
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An important thing to remember about the new-style studs. They are no less likely to back-out than the original studs are. The new ones are simply easier to install. That is the only advantage.

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No harder than the originals.
 
I am about to install my new style studs when I get them.
I understand the need to secure the stud. But also in the North East I have to worry about removal 5 years from now. So the concern is not only about the studs getting loose, but the need to R&R in the future. So far all the information I gather deal with one issue or the other. Meaning: Anti-seize, locktite or nothing.

I hope this thread will be helpful in arriving to a consensus to the following question:
What is the best compromise between securely keeping the knuckle studs torqued correctly and the need to remove them in the distance future taking into account salt and rust.

Specifically
1. Does anti-seize grease will allow the studs backing out in time? (it is good for rust)
2. Will locktite prevent easy removal of studs if needed? (it is good for studs not backing out)
3. Will locktite prevent rust (good for long term removal depending on 2)
4. Is no additive the best overall? (long term exposure to salt will be a problem)

When I took the studs off, 7 came out with the double nut method. One did not budge, and only pipe wrench got it off destroying the stud.

Again a best compromise is what will be the most useful given North East US conditions.
 
timmbuck2 said:
....... I want to try and figure out what is happening here, other than neglect by me in checking this on my rig after wheeling trips and before long trips.....
........My main question is how are these studs working free? What would cause this? It seems like it happens after a axle job, but what could I do to the knuckle to make these studs work themselves free?? ........
Click to expand...

Interesting story - thanks for sharing - we all need to know what can happen.

Anyway, I think that the main thing to understand is that this is what is referred to as "sequence sensitive" during re-assembly. In other words, step 1 MUST be performed BEFORE step 2 or you might as well be doing something else. Step 1 being: installing the studs at proper torque - Locktite, alone without proper torque, is still insufficient. This step is necessary to provide the base for the nuts, which will be torqued later. If it's not right, the whole knuckle assy is at risk, as you and others have experienced. Step 2 is to continue re-assembly.

I would venture to say, if you check the nuts and they need re-torquing more than once, your studs are probably loose. And if they're loose, torquing the nuts is an exercise in futility - they'll work loose again. It would be best to tear it down and torque the studs correctly.
 
Excelent observations.
 
I've been following these knuckle stud threads for a while - especially after mine failed 20K miles after the rebuild. My personal opinion is that if you don't get the studs in the knuckle right to begin with, you will have a failure. I think once they start to loosen up, failure happens quickly. I don't think checking them every oil change/fill up/1000 miles is good enough if they weren't put in well to begin with.

When I re-did my passenger side, I used Loctite on the studs. I'm still on the fence with that though. If the studs are torqued properly, they shouldn't need the Loctite. But, after having a failure, I didn't want to take the chance again.

Tom
 
I'm going to red loctite my new studs and of course torque them to proper specs...

The risk I see would be getting them out down the road but the only reason I would need to get them out IMO would be if one sheared off and at that point I've got bigger issues...My thought is that I would rather just replace the knuckle with a new one with new studs down the road (despite that cost) than have them loosen and have me lose steering on a shelf road or driving down the interstate.

I'm condering putting blue loctite on the nuts as well...Full front end service is every 60K miles right? For me that is probably 10 years of driving and by then all the trails will be closed anyway :frown:
 
Aren't these safety wired on 40's? Has anyone thought about a similar solution?
 
Not from the factory.
 
Ebag333 said:
Aren't these safety wired on 40's? Has anyone thought about a similar solution?
Click to expand...

I helped a guy recently on a 55 front end rebuild. The bolts that were safety wired were the bolts that held the hub to the knuckle. Seems like safety wires on the knuckle studs and nuts might catch on stuff and break rather easy. I like the idea, though. Something foolproof in that area would be tough.
 
I check these every day on the trail. Takes two minutes and it's my end of the day ritual.

At Rubithon this year, I had every single person check the knuckle studs before we started. Did not break any in 3 days of wheeling in a group of almost 20 trucks.

CDan is the expert, but, the newer studs appear to be made of better material, at least to me, and Luke Porter recommends them above the ARP studs.

I would be afraid to torque the studs into the knuckle to 50 foot pounds. Once you get into this range it feels like the base metal of the knuckle wants to give way. Toyota does not publish a torque spec for this that I have seen. I go more like 30. I did not used to believe in Locktite, since it would make a broken stud hard to remove. However, now I am convinced they break infrequently enough, that LockTite on balance is probably beneficial.

It's interesting, but I have seen dozens of these broken at events like Rubithon, and one poor dude who sheared a full set last year on Fordyce right as the sun was going down. He spent the entire night wrenching, just to get off the trail. I have never personally broken one, but I know I'm due.

There is a cool mod where thicker and heavier D44 studs/cones are used. Has anyone done that in an 80?
 
red 271 locktite on mine. I chase the holes with a tap and isopropyl alcohol prior to install.

For those doing this it will take a torch, preferably MAP gas, to heat the knuckle enough to crystallize the locktite and allow removal.

We use this technique on the equipment I service and that stud will shear clean off before it begins to back out.
 
What size and type tap is used (never used a tap before). What is the consensus on the torque spec for new studs?
 
Interesting, I just went through this issue not knowing. The way I found out was while driving, the truck developed a front end shimmy and was hard to control when hard braking. When I lifted the truck, I noticed the front right wheel assembly was loose. Discovered that one stud was missing and the remainder three were loose. I ordered all new studs, and as of now, I'm still running with three studs on the right side and one stripped on the left side and still waiting for the studs to arrive. I'll try to post some pics of the mess I have right now.:cheers:
 
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