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Discussion Starter #1
In the gear grinder thread I mentioned I had to replace the left front tire on my 2WD X754 due to a sidewall puncture.

OK; there is only one bolt holding the front wheels on 2WD models, and they are torqued to 54 lb/ft. I can get the bolt torqued to 40 lb/ft with any value above that never achieving the set value on my torque wrench. It feels like the bolt wants to break; so I back off. I check the right front wheel bolt that has never been disturbed since I bought the machine new, and it clicks just fine at 54 lb/ft per the shop manual.

The shop manual makes no mention of replacing the bolt if it was removed with a new one. In other words, WTF?

I'll probably just get a new bolt and call it good.
 

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Get a new bolt.

A bolt is like a spring.

When I had assembly at an engine factory that was a two hour class the engineers taught to new hires and they had some cool teaching aids to demonstrate.

Basically you stretch a bolt each time you tighten it. We actually measured 2 times a shift every critical fastener going on before and after installation. We measured with ultrasound. If the bolt did not elongate in the proper range we had bad bolts.

We torqued allot to yield. The bolt stretches to a point and plateaus. (yield). If you go past that it becomes overly stretchy (rubbery) until it breaks. Each time you tighten and loosen a bolt it's yield is reduced. Once a bolt is over yield or used too many times it’s scrap.

A single bolt holding a wheel sould have a max number of uses but it may be high enough it’s not statistically likely you would remove the wheel enough times to ruin the bolt in it’s life.

Also there are just bad bolts, they harden them in big baskets and they can clump if the process is not properly followed.

Some bolts have special coatings. We had turbo bolts that were machined inconclusive coated in pure copper and then top coat of 99.7% pure silver. $45 dollars a bolt. You ran 4 in at once, if a torque gun errored during run down all 4 were scrap since it scrapes the silver off as you run them in and out.
 

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MJ, Meager is 110% correct. A bolt NEEDS to be stretched in order to hold. How much "stretch" is determined by the torque applied.

You could have one of several situations here. Hopefully, the threads in the axle are still good, otherwise a heli-coil or thread-sert is needed. I'm betting the bolt is bad. Did a previous owner replace it with a "softer" bolt...check the bolt on the other wheel for markings. The bolt may have been over tightened by a previous owner also.

Bottom line is to get a new bolt of the SAME grade as the other wheel. As a side note, are you lubing the threads AND under the head before torquing? This is critical as a dry bolt requires 10-15% more torque to get the same "stretch" on the bolt.

BTW, VERY smart move on your part to stop torquing and remove the bolt. Bob
 

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We may all be saying the same thing a bit differently, but my take is as follows.
Graded bolts have a yield strength, which is the point at which deformation occurs that it cannot recover from, or the point at which damage occurs to the fastener. If its a graded bolt, its definitely NOT a torque to yield bolt. You can tell by the marks on the head.

Several systems these days are designed with "TTY" (torque to yield) bolts. Now, I could take some of the above to mean that all bolts are in the TTY category, but I disagree.

If that was the case on all bolts, there would be an AWFUL lot of wheels falling off going down the highway.
Heck, there would be a whole lot of everything falling apart everywhere if that were the case.
My VW has 335,000 miles on it. Any idea how many times the wheels have been off of that thing in that amount of time? If all bolts wore out from stretching every time, my wheels would have fallen right the heck off about 150,000 miles ago.

Its all in how the engineers designed the parts, and the specs they wanted. If its truly a torque to yield bolt, youd know it, because it would be mentioned in the manual, and on JDParts.
The torque spec also isnt just a number. It will be a number, then so many degrees past, or something similar. Its never a one step tightening spec.

There is certainly nothing wrong with replacing it, but Id be sure it wasnt a problem in the assembly that caused the issue, and that my torque wrench had been recently calibrated (something that almost no one does with torque wrenches in home shops), or have a type that doesnt require calibration, though those are few and far between.

See, having an engineering background, I like to know a lot about why things are the way they are. When I bought my VW some years back, I ran into all sorts of TTY bolts on that thing. I got to looking into it a bit. Well, maybe more than a bit. Anyway, the point is, they are EVERYWHERE on European cars. They also are NOT lots of places on those same cars. They have their uses, but not every bolt will break simply from normal use and re-use. I can say too that not a single one of them has marks on the heads (thats why I mentioned above about the whole graded bolt markings thing).

Anyway, I hope you get it sorted out.
 

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Discussion Starter #5
You could have one of several situations here. Hopefully, the threads in the axle are still good, otherwise a heli-coil or thread-sert is needed. I'm betting the bolt is bad. Did a previous owner replace it with a "softer" bolt...check the bolt on the other wheel for markings. The bolt may have been over tightened by a previous owner also.

Bottom line is to get a new bolt of the SAME grade as the other wheel. As a side note, are you lubing the threads AND under the head before torquing? This is critical as a dry bolt requires 10-15% more torque to get the same "stretch" on the bolt.

BTW, VERY smart move on your part to stop torquing and remove the bolt. Bob
I'm the original owner. Maybe Deere's torque wrenches were out of whack the day the wheels were put on. Once in a while I do something smart as the last thing I want to do is screw up the front axle.

There is certainly nothing wrong with replacing it, but Id be sure it wasnt a problem in the assembly that caused the issue, and that my torque wrench had been recently calibrated (something that almost no one does with torque wrenches in home shops), or have a type that doesnt require calibration, though those are few and far between.

Anyway, I hope you get it sorted out.
My click type torque wrench has never been calibrated, and it's at least 40-years old. :laugh: I don't use it often, nor have I abused it. I can't even tell you what brand it is without running out to the garage. It was what I could afford at the time that wasn't a beam or dial type that's a pain in the butt to read. Given its age, I consider it a get it in the ballpark type of tool. I also reset it to the lowest value when I'm done.

I've just never had a bolt do this after just one use that I can recall. I'll just get a new one the next time I head into town.

Thanks gents.
 

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Watching to see what you find. Bad bolt? Or bad threads in the spindle? Please post when you find out. :munch:
 
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I understand the TTY bolts and all that but I think that like most engineers they are over thinking this.:lol:

I'd pull it out, clean both the bolt and the tapped hole, look the threads over. Assuming you can't see any issues I'd then clean the hub and the mounting surface, inspect and reinstall. Lube up the tapped hole and the bolt and Torque the bolt in to spec. If the bolt breaks which I'd doubt it will or the tapped hole strips (most likely) then look at fixing tapped hole. If your tapped hole is bad its bad, nothing can fix it now. Reassembling the works you'll find out whats what.
 

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Discussion Starter #10
Welcome to GTT, Denverguy. It's nice to have another Colorado guy on GTT, or are you from Denver, NC?

I hope to make time this weekend to replace it.
 

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klunker - I'm an engineer also, so please let me add my "overthought" thoughts:

I found this on the internet: https://web.archive.org/web/20120107233624/http://www.acl.co.nz/Tech/Torque To Yield Headbolts.pdf

This article speaks to cylinder head bolts, which would experience different forces than wheel bolts.

It's worth also considering that in order to stretch and load the body of a bolt, the male and female threads have to align and hold; Ant debris that interferes with thread engagement defeats the purpose.

I spent my professional life in oil and gas. In the offshore environment where costs are high, we carried extra pipe and couplings for each job. We had computerized torque "make-up" machines that allowed real time evaluation of each connection as it was made. We liked to "fail fast" in the event of a suspect connection in order to keep things proceeding forward. Applying the correct thread compound ("pipe dope") in the proper fashion helped also; one did not just slather it on and hope for the best.

Brian



I understand the TTY bolts and all that but I think that like most engineers they are over thinking this.:lol:

I'd pull it out, clean both the bolt and the tapped hole, look the threads over. Assuming you can't see any issues I'd then clean the hub and the mounting surface, inspect and reinstall. Lube up the tapped hole and the bolt and Torque the bolt in to spec. If the bolt breaks which I'd doubt it will or the tapped hole strips (most likely) then look at fixing tapped hole. If your tapped hole is bad its bad, nothing can fix it now. Reassembling the works you'll find out whats what.
 

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klunker - I'm an engineer also, so please let me add my "overthought" thoughts:

I found this on the internet: https://web.archive.org/web/20120107233624/http://www.acl.co.nz/Tech/Torque To Yield Headbolts.pdf

This article speaks to cylinder head bolts, which would experience different forces than wheel bolts.

It's worth also considering that in order to stretch and load the body of a bolt, the male and female threads have to align and hold; Ant debris that interferes with thread engagement defeats the purpose.

I spent my professional life in oil and gas. In the offshore environment where costs are high, we carried extra pipe and couplings for each job. We had computerized torque "make-up" machines that allowed real time evaluation of each connection as it was made. We liked to "fail fast" in the event of a suspect connection in order to keep things proceeding forward. Applying the correct thread compound ("pipe dope") in the proper fashion helped also; one did not just slather it on and hope for the best.

Brian
Just so we understand ea. other.

My first comment on TTY and over thinking was that the wheel bolt the OP talked about having issues with is not a TTY bolt.
SO all the talk of TTY bolts, while interesting, has no bearing on his problem.

The rest of your comment I'm taking it as you don't think that oiling or greasing bolts/tapped holes before ass'y is a good policy.
Here we would differ. Now talking wheel bolts and or studs/nuts for fastening wheels to hubs and even the wheel to hub mating surfaces.
I ALWAYS lube up these things before ass'y. On my cars I use grease and apply it to the hub/wheel mounting surfaces after cleaning but before mounting the wheel.
When installing the the wheel bolts into the tapped holes of the hub I grease them also. And when I say grease them I do "slather" it on as you suggested. I torque all bolts after tightening and then double check the torque before calling the job done. The car I have now uses wheel bolts rather than studs/nuts. I do like the wheel bolts over studs/nuts, I think its a better design.
I suggest greasing as it solves issues of rust/corrosion which is a bigger problem in my area than the non-existent problem that doing it will cause the wheels to fall off or bolts to come loose.


Arguing that greasing vs using the proper thread compound is irrelevant in wheel assemblies. I'll bet that during assembly the bolts are just torqued, there is no thread compound added. The only lube is whats on the pieces left over from manufacturing and corrosion prevention.

Your mentioning on how your experiences in the oil and pipe line world while interesting is not the same as the tire/wheel world and reminds me of all the TTY stuff. Interesting but not relevant to wheel bolts.

But maybe I'm wrong about the intent of your post. If so I apologize. I toss all this stuff out there not to say I'm right and your wrong but as anothers view with over 40 years experience working on cars.

TTY and thread ass'y compounds are used on how many of the threaded assemblies in your tractors? less than 10%? probably less than 1%.
 

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klunker - No apology necessary. I added the TTY link for educational purposes only.

As a guy whose livelihood was and is still partially provided by oil and natural gas, I by all means promote the use of grease on threads for anti-corrosion and anti-seize purposes. I once galled threads on a cylinder head on an outboard motor. After having the threads chased, we never replaced spark plugs on any of the cylinders without adding anti-seize compound.

I agree with your assessment that little or no lube is used during assembly, as it would add time and material to the process (read money).

Brian

Just so we understand ea. other.

My first comment on TTY and over thinking was that the wheel bolt the OP talked about having issues with is not a TTY bolt.
SO all the talk of TTY bolts, while interesting, has no bearing on his problem.

The rest of your comment I'm taking it as you don't think that oiling or greasing bolts/tapped holes before ass'y is a good policy.
Here we would differ. Now talking wheel bolts and or studs/nuts for fastening wheels to hubs and even the wheel to hub mating surfaces.
I ALWAYS lube up these things before ass'y. On my cars I use grease and apply it to the hub/wheel mounting surfaces after cleaning but before mounting the wheel.
When installing the the wheel bolts into the tapped holes of the hub I grease them also. And when I say grease them I do "slather" it on as you suggested. I torque all bolts after tightening and then double check the torque before calling the job done. The car I have now uses wheel bolts rather than studs/nuts. I do like the wheel bolts over studs/nuts, I think its a better design.
I suggest greasing as it solves issues of rust/corrosion which is a bigger problem in my area than the non-existent problem that doing it will cause the wheels to fall off or bolts to come loose.


Arguing that greasing vs using the proper thread compound is irrelevant in wheel assemblies. I'll bet that during assembly the bolts are just torqued, there is no thread compound added. The only lube is whats on the pieces left over from manufacturing and corrosion prevention.

Your mentioning on how your experiences in the oil and pipe line world while interesting is not the same as the tire/wheel world and reminds me of all the TTY stuff. Interesting but not relevant to wheel bolts.

But maybe I'm wrong about the intent of your post. If so I apologize. I toss all this stuff out there not to say I'm right and your wrong but as anothers view with over 40 years experience working on cars.

TTY and thread ass'y compounds are used on how many of the threaded assemblies in your tractors? less than 10%? probably less than 1%.
 
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Discussion Starter #15
I replaced the OEM bolt today with one that is the same 10.9 grade (~Grade 8). Obviously Deere and/or I put more than 54 lb/ft on the OEM bolt, which measured ~25mm in length compared to the replacement’s 20mm length. Maybe the OEM bolt is made of Chinese Alumisteel.

Deere's shop manual just lists a torque value, and does not specify whether that is dry or lubed. I didn't clean out any grease in the spindle threads.

Here's the OEM bolt and replacement side by side.


 

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I replaced the OEM bolt today with one that is the same 10.9 grade (~Grade 8). Obviously Deere and/or I put more than 54 lb/ft on the OEM bolt, which measured ~25mm in length compared to the replacement’s 20mm length. Maybe the OEM bolt is made of Chinese Alumisteel.

Deere's shop manual just lists a torque value, and does not specify whether that is dry or lubed. I didn't clean out any grease in the spindle threads.

Here's the OEM bolt and replacement side by side.
the original bolt was longer than the replacement, count the number of threads.
Other than that I have never seen a bolt strech so bad that you could visibly see it.
I have spent over 40 years working on cars, owned a business where we purchased tens of thousands bolts per year.

I would suspect the original bolt was sourced from china.
Deere being anything but a low price item better watch out, this kind of stuff will ruin a company.
 

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I replaced the OEM bolt today with one that is the same 10.9 grade (~Grade 8). Obviously Deere and/or I put more than 54 lb/ft on the OEM bolt, which measured ~25mm in length compared to the replacement’s 20mm length. Maybe the OEM bolt is made of Chinese Alumisteel.

Deere's shop manual just lists a torque value, and does not specify whether that is dry or lubed. I didn't clean out any grease in the spindle threads.

Here's the OEM bolt and replacement side by side.
What makes you think the original bolt stretched?

The original bolt is P/N 19M7785. As you can see from the specs below it is a 10mm grade 10.9 bolt that is 25mm long with a 1.5 thread pitch. There is no way that this bolt is going to stretch to the point that you can see it visually. Which is why bolt stretch is typically measured with a dial gauge.

Part Number:
19M7785
Part Price: 0.97 USD Each
On Hand:
32 Check Other Stores
Description: Screw - SCREW, FLANGED, METRIC
Package Quantity:
50 (Contact your dealer for lower quantity availability)

Specification
Weight: 0.07 LBS 0.03 Kg
Thread Size10.000 MM
Thread Pitch1.500 MM
Length25.000 MM
Thread Length20.500 MM
Flange Diameter22.300 MM
Head Height10.400 MM
Material or Grade10.9
Drive Size15.000 MM
FinishB
Note

When you see torque specs listed in your operator's manual they are all for DRY bolts - no lube.

It's odd that the operator's manual only instructs you to check the torque on the lug bolts for the rear wheel - which they give the torque value. It says nothing about checking the front tire bolt nor does it list the torque specification.

I suspect this information would be in the Technical Manual rather than the operator's manual.
 
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What makes you think the original bolt stretched?
Its plainly visible that the bolt stretched.
Look at the threads under the head, the first couple of threads have a noticeably bigger pitch.
Not a mfg defect as its almost impossible to roll threads with variable pitch.
Those threads where rolled, not cut.

Just cause spec calls out grade does not mean bolt iis to spec.
That is most likely cause, bolt not to spec, bolt made from butter steel, bolt stretched.

Look for who mfg bolt/country of origin. That will answer all your problems.

I'll bet $20 it was from China.
 

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Its plainly visible that the bolt stretched.
Look at the threads under the head, the first couple of threads have a noticeably bigger pitch.
Not a mfg defect as its almost impossible to roll threads with variable pitch.
Those threads where rolled, not cut.
Thanks for pointing that out. I looked at that photo for a while but somehow didn't notice those threads.
 
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