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Catastrophic Knuckle Failure (1 Viewer)
- Thread starter brettwilm
- Start date
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2fpower
SILVER Star
Can we get a PSA (public service announcement) or sticky about checking your nuts so you don't lower your steering arm!
-- not to be confused about how to lower your PSA by playing with your nuts.
https://prostate.net/articles/10-ways-to-lower-your-psa
makes me think of John Candy....
-- not to be confused about how to lower your PSA by playing with your nuts.
https://prostate.net/articles/10-ways-to-lower-your-psa
makes me think of John Candy....
Malleus
Far west of Siegen
No way to tell, but that's as likely as not.
Malleus
Far west of Siegen
The torque value is typically calculated based on the thread diameter, and if it's a known failure point, the tensile force it usually sees, or is expected to see. So there is not any reason I can think of to reduce the installation torque. You're correct that grabbing this shoulder is a problem, but there's a snubber made for this, even though I've never seen anyone use one. This is why most manufacturers don't use them, unless they can install them on the assembly line. The process is typically to use two nuts, jammed together, and then stake the stud. This reduces the deformation resulting from using two nuts to drive the stud, and prevents (hopefully) the stud from backing out.
I'm surprised Toyota didn't do this. It's typical for SAE and aviation in the US.
In my case.it was not a.stud torque.issue. I did not remove studs when rebuilding axle 2 years ago.
It.was a sheared stud. Didn't check studs when leaving trail and 130 miles.later all hell broke.loose.
Leson learned.
Never leave trail without checking those studs. In fact everyone should do a quick visual inspection or you may end up like me.
Glad that happened in front of your house!!
- Thread starter
- #28
Cleaned off sheared stud end from post #7. I guess this thing is a hero because it was keeping my steering together by itself until it failed. I have the cone washer, flat washer, and nut back on.
I'm told there is supposed to be a fitting on the end of this stud so it can be torqued into the knuckle. I don't see any fitting you can put a wrench on, on the end of this. Does anyone think this is was a hand-tightened hardware store part from PO or am I missing something? Would a mechanic have ground it off?
I'm told there is supposed to be a fitting on the end of this stud so it can be torqued into the knuckle. I don't see any fitting you can put a wrench on, on the end of this. Does anyone think this is was a hand-tightened hardware store part from PO or am I missing something? Would a mechanic have ground it off?
Cleaned off sheared stud end from post #7. I guess this thing is a hero because it was keeping my steering together by itself until it failed. I have the cone washer, flat washer, and nut back on.
I'm told there is supposed to be a fitting on the end of this stud so it can be torqued into the knuckle. I don't see any fitting you can put a wrench on, on the end of this. Does anyone think this is was a hand-tightened hardware store part from PO or am I missing something? Would a mechanic have ground it off?
View attachment 1548563
That looks to be a correct, original stud that was sheared off. Each stud has a stud, cone washer, flat washer, nut. Do NOT lubricate them when you assemble. They should be CLEAN AND DRY. (unless you decide to use Loctite....)
You had essentially the same issue as mine. I forgot to mention that on mine, one was sheared off, two unscrewed and fell out, and one was hanging on by one or two threads. You last one sheared off as you pulled into your drive.
The NEW factory studs will have a make Torx head to them in order to accept a socket. That tip shears off pretty low in the toque range. I used the double-nut method to torque mine into the holes (as everyone states NOT to do) and I also used the Red Loctite.
You can buy all (4) cones, washers, nuts, and studs for about $12 per stud assembly, so $50 per side of the truck.
Many folks that wheel a lot check their nuts both before and after they are on the trail. Then they just play with them while they're out.
My 93 still has original style studs that I have re-set using the double nut method for three knuckle jobs in 200,000 miles and 25 years. I'll go out on a limb and knock on wood, I have never had one back off yet.
- Thread starter
- #31
OK thanks. I bought a replacement hardware kit from NLXTACY; it has torx heads and comes with a matching socket--nice. Will attempt to remove the sheared stud end with an ez-out. Thank you for the install tips. If steering remains gimpy after I replace the studs, I'll replace the knuckle. Looking at a knuckle/birf resto soon anyway....
The key is making sure everything is CLEAN AND DRY when reassembling.
The lower arm needs to be thumped with a deadblow hammer over and over during the final torquing process in order to make sure it gets COMPLETELY seated. (Don'[t forget to grease your trunnion bearings!)
There are a number of threads on this subject, do a search if no one is answering in a timely manner!
ToyotaDon
I am here
I agree with what you've been saying, except for this (unless you are indicating it was instead a nut torque issue).
All the textbooks/experts say: "Fatigue breaks are the most common type of fastener failure. A bolt becomes fatigued from working back and forth when it is too loose. Under-tightening the bolt causes this problem."
Torquing a bolt stretches it to about 70% of its elastic limit (the point at which it will not return to its original shape) and in this case, the final tightening of the nut is what stretches the stud to that point.
HTH
surfpig
The Anti-Tech
Checking mine as we speak!
OP: I'm glad you are safe, and thanks for the reminder for us all.
n
Just curious, is this a problem unique to the 80 or do all solid axle trucks have this issue? Don't ever remember reading about this on the 40 section or the pickups.
Cruiserdrew
On the way there
Any traditional Toyota solid axle set up. If anything, I've seen more trail failures in mini-trucks, but they tend to be wheeled hard and put away wet, so who knows. This problem is certainly common in 80s. Check them at every oil change and every day on the trail.
One of these is really good to have in your tool kit:
VIM Tools DPW1417 Extra Long 14mm x 17mm Offset Drain Plug Wrench
One of these is really good to have in your tool kit:
VIM Tools DPW1417 Extra Long 14mm x 17mm Offset Drain Plug Wrench
surfpig
The Anti-Tech
Mine were just a bit loose from spec.Checking mine as we speak!
OP: I'm glad you are safe, and thanks for the reminder for us all.
n
I also topped off my passenger side knuckle grease, using the cake frosting method with the grease I had laying around. That one seems to indicate early signs of an oil seal failure.
Sorry, I still am unclear...are the studs not being properly torqued into the knuckle, or the nuts not properly torqued on the studs?
When removing the steering arm, you obviously just remove the nut, and the stud is just there in the knuckle. I'd assume that the stud wouldn't loose torque within the knuckle when servicing, but it sounds like that isn't the case, and should be re torqued using a double nut method or similar.
In my experience, I would think that this application would call for a locking compound (blue) with reduced torque value. I have access to all ASME, NAS, MIL, etc specs at work, I'll look and see what I find.
When removing the steering arm, you obviously just remove the nut, and the stud is just there in the knuckle. I'd assume that the stud wouldn't loose torque within the knuckle when servicing, but it sounds like that isn't the case, and should be re torqued using a double nut method or similar.
In my experience, I would think that this application would call for a locking compound (blue) with reduced torque value. I have access to all ASME, NAS, MIL, etc specs at work, I'll look and see what I find.
That's a debate that has raged for years. My opinion is that stud torque doesn't matter much as the nut torque is transferred throughout the fastener, pulling equally on the nut threads and the knuckle threads. In fact, I'd go so far as to say that you risk messing up the threads on the knuckle side by torquing the stud- what's stopping the stud? Probably the tiny shoulder mashing into the knuckle thread. I believe that the steering arm wasn't seated properly and as it moves around the nuts lose torque and eventually walk out far enough that the movement in the steering arm destroys them. I also believe that using thread locker makes it impossible to check the torque later. If I were going to use it, I'd only use it on the knuckle end of the stud.
On the other hand, many people torque the studs without issue, so there's no clear 'right' answer.
Malleus
Far west of Siegen
FWIW, the only problem with the double nut method is that if you happen to line them up so that you grab both at the same time, you risk deforming the thread between them. If you only grab one, it's the same as turning the head on a bolt or screw.
