F150 Powerboost Axle bolt sheared off

[alkoser]

That isn't really a legitimate way to torque. The appropriate way would be to say, the bolt and bolted joint should be fully seated and then another 90 degree turn. This could very well be how it was done to determine the 52 ft/lbs, but the required torque for a bolted joint varies GREATLY depending on thread friction.

But then the problem becomes, how do we know when all components are fully seated? It is easy to define, but not as easy to tell when actually assembling, knowing you only have about 45 seconds to install that bolt plus whatever other components you have to install. Again, the torque values change greatly, depending on thread friction. Some bolts may only need 38 ft/lbs (random number) if the fastener is well lubricated, so 52 ft/lbs could be another 45 degree turn past 38 ft/lbs and then you're adding another 90 degree on top of that, which could put the torque value much higher than even your 120 ft/lbs.

I wonder what measures they have in place in the plant to determine the 90 degree turn. They either have a poor process, or the process isn't being followed, both of which are totally possible. It is also highly possible that the amount of the red loc-tite on the threads greatly affects how much torque is required. Ultimately, I think the best solution for Ford to implement, would be to use a bolt with much higher yield strength. It will make all of the above variables a moot point.

/rant

Would be nice if they cared about customer satisfaction/feedback buuuut...

Considering Ford is first and foremost a business, you can bet that they have not seen a significant monetary loss on dealing with these broken bolt warranty repairs. They just sell so many damn new trucks that is hardly affects their bottom line. That is the one and only reason why they have been publicly silent about a real solution. Money is the only thing that matters here. They don't care if people complain as long as they're ordering the 2023 model just as happily as before. I hate it.

/rant also

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[780]

Well that did it. I had an old plastic work badge that is a little more flexible than a credit card and it worked as you described. I only checked the driver's side. I'll check the passenger tomorrow. I'm officially on the list. My dealer's website says next available appt is end of December. I'll call them tomorrow and see what they can do. Thank you!

First pic is what it looked like when I got the cap removed.

So the tip off was that you were hearing the bolt banging around the wheel?
Just trying to determine what I should keep an eye / ear out for.

No PowerBoost but 3.5 Eco Max Tow w/ 3:55's.

Not sure if it's all Max Tow pkgs that seems to be inflected or if it's just PowerBoost w/ 3:73's?

 

[dolsen]

Would be nice if they cared about customer satisfaction/feedback buuuut...

Considering Ford is first and foremost a business, you can bet that they have not seen a significant monetary loss on dealing with these broken bolt warranty repairs. They just sell so many damn new trucks that is hardly affects their bottom line. That is the one and only reason why they have been publicly silent about a real solution. Money is the only thing that matters here. They don't care if people complain as long as they're ordering the 2023 model just as happily as before. I hate it.

/rant also

Agreed, I've seen it first hand many times. What Ford will do is they will quietly acknowledge and fix it internally, but never publicly acknowledge it. Then you have the soft acknowledgement where they'll say it is normal (transmission shudders), or that it is an anomaly (engine fires).

 

[UGADawg96]

So the tip off was that you were hearing the bolt banging around the wheel?
Just trying to determine what I should keep an eye / ear out for.

No PowerBoost but 3.5 Eco Max Tow w/ 3:55's.

Not sure if it's all Max Tow pkgs that seems to be inflected or if it's just PowerBoost w/ 3:73's?

yes, I heard a clanking sound at parking lot speed with the radio off.

It affects all Max Tow trucks regardless of PB or not.

I'm not a fan of the other site, but there is a thread tracking the failures:

https://www.f150forum.com/f129/2021...axle-bolt-sheared-515460/index21/#post7265683

 

[780]

yes, I heard a clanking sound at parking lot speed with the radio off.

It affects all Max Tow trucks regardless of PB or not.

I'm not a fan of the other site, but there is a thread tracking the failures:

https://www.f150forum.com/f129/2021...axle-bolt-sheared-515460/index21/#post7265683

Crap. Hope they get it fixed fast for you.

 

[UGADawg96]

Dropped off truck this morning. They gave me a Jan 21 built F150 King Ranch Ecoboost with 50k miles via the Enterprise location next door to them. Weird driving a short bed with no tow mirrors. First time seeing the full digital dash. Man those power steps are loud when they actuate.

 

[dolsen]

Dropped off truck this morning. They gave me a Jan 21 built F150 King Ranch Ecoboost with 50k miles via the Enterprise location next door to them. Weird driving a short bed with no tow mirrors. First time seeing the full digital dash. Man those power steps are loud when they actuate.

I prefer the 8" cluster over the 12". I just don't like the artwork of the gauges and cluster. I prefer the look of rel gauges, even if they are all digital

 

[notabot]

This was posted, #640, in the other forum thread :

In the 2021 Service Manual, it says to torque the axle bolt to 100 ft-lbs. In the 2022 service manual, it says to torque it to 52 ft-lbs and then 90 degrees. The procedure in the FSM was updated on 3/26/22 so Ford did realize something was going on.

So if that’s true it would indicate the bolt was originally under torqued by 20# per your measurement when installing to the new spec.

Pic below is from my 2021 service manual:

 

[Buyer2021]

That isn't really a legitimate way to torque. The appropriate way would be to say, the bolt and bolted joint should be fully seated and then another 90 degree turn. This could very well be how it was done to determine the 52 ft/lbs, but the required torque for a bolted joint varies GREATLY depending on thread friction.

But then the problem becomes, how do we know when all components are fully seated? It is easy to define, but not as easy to tell when actually assembling, knowing you only have about 45 seconds to install that bolt plus whatever other components you have to install.

Just FYI the only two "components" are the axle shaft and the wheel hub (a complete sealed / non-serviceable assembly with bearings inside).

Further FYI the Ford Workshop Manual procedure for installing the axle shaft calls for using a hydraulic press to seat the axle shaft in the wheel hub (remote from the vehicle) before installing the end-bolt. Using that procedure on a hydraulic press it should be quite obvious when the inside face of the wheel hub bearing is 'fully-home' against the lip machined in the axle and the washer against that lip which serves as the 'depth stop'.

That procedure ensures "all components are fully seated" without using the bolt to achieve that objective. I suggest that by adhering to that procedure the bolt torque (installed 'dry' because it is to be replaced with new if removed and is packaged pre-coated with locking compound, which ensures within reason relatively consistent 'thread friction') would then serve only load and retain the bolt itself.

Insofar as factory procedures for achieving 52ft-lb + 90°, that's an extremely easy, common, and very consistently repeatable task to program into an automated production-line torque tool.

EDIT - COMPLETE WSM PROCEDURE ATTACHED

EDIT #2 - If one reads the WSM procedure it should be obvious that simply extracting a broken bolt and installing a new one in-situ is fraught with potential for repeated failure. IMO it is critical that the axle shaft+wheel hub assembly be removed from the vehicle to ensure that those two components are "fully seated" as they should / must be before the bolt is installed. IMO it's a mistake to thinks that "seating" which is intended to be accomplished by use of a hydraulic press can be properly effected by tightening the end-bolt.

 

[dolsen]

Just FYI the only two "components" are the axle shaft and the wheel hub (a complete sealed / non-serviceable assembly with bearings inside).

Further FYI the Ford Workshop Manual procedure for installing the axle shaft calls for using a hydraulic press to seat the axle shaft in the wheel hub (remote from the vehicle) before installing the end-bolt. Using that procedure on a hydraulic press it should be quite obvious when the inside face of the wheel hub bearing is 'fully-home' against the lip machined in the axle and the washer against that lip which serves as the 'depth stop'.

That procedure ensures "all components are fully seated" without using the bolt to achieve that objective. I suggest that by adhering to that procedure the bolt torque (installed 'dry' because it is to be replaced with new if removed and is packaged pre-coated with locking compound, which ensures within reason relatively consistent 'thread friction') would then serve only load and retain the bolt itself.

Insofar as factory procedures for achieving 52ft-lb + 90°, that's an extremely easy, common, and very consistently repeatable task to program into an automated production-line torque tool.

EDIT - WSM PROCEDURE ATTACHED

Good to know. I do not know much about how the axle and hub are assembled, my response is more for bolted joints for items that are not friction fit together.

However, while the process may be easily repeatable, what is not necessarily so easily repeatable is ensuring that the thread friction is identical from bolt to bolt, axle shaft to axle shaft. Too much or too little loc-tite, or any other foreign matter in or on the threads, could profoundly change the required fastening torque. A slightly extreme example of this could be getting some sort of foreign matter in the threads (weld slag, sand grit, etc.) and this could cause your pre-load torque to be higher than your required torque for full seat, and you could have a fully torqued bolt that isn't even fully seated. The automated production line tooling wouldn't know any difference.

I actually misspoke earlier, PROPER torque would be to fully seat the bolt, plus 1/4 turn. NOT hitting a certain torque and then another 1/4 turn. You would use a torque wrench to hit that last 1/4 turn and read the torque once you hit 90 degrees. From there you give a tolerance, something like +- 10% would be good for an application like this. That's where the issue lies and almost certainly is introducing over torqued bolts, as evidenced by all of the bolt failures.

The more I think and expand on this, it's most likely they need to use a higher grade bolt. The torque seems appropriate for the application, but the bolt cannot withstand the torque

 

[Porpoise Hork]

The more I think and expand on this, it's most likely they need to use a higher grade bolt. The torque seems appropriate for the application, but the bolt cannot withstand the torque

I wondered about using a higher grade non torque to yield bolt instead. The only thing special about the oem bolt assembly is the filler compound they used in the washer. The washer can be removed without damaging this filler material. I may get a pair of alloy grade BD or 8 bolts if the replacements I installed with the updated specs happen to fail.

 

[Buyer2021]

However, while the process may be easily repeatable, what is not necessarily so easily repeatable is ensuring that the thread friction is identical from bolt to bolt, axle shaft to axle shaft. Too much or too little loc-tite, or any other foreign matter in or on the threads, could profoundly change the required fastening torque. A slightly extreme example of this could be getting some sort of foreign matter in the threads (weld slag, sand grit, etc.) and this could cause your pre-load torque to be higher than your required torque for full seat, and you could have a fully torqued bolt that isn't even fully seated. The automated production line tooling wouldn't know any difference.

I actually misspoke earlier, PROPER torque would be to fully seat the bolt, plus 1/4 turn. NOT hitting a certain torque and then another 1/4 turn. You would use a torque wrench to hit that last 1/4 turn and read the torque once you hit 90 degrees. From there you give a tolerance, something like +- 10% would be good for an application like this. That's where the issue lies and almost certainly is introducing over torqued bolts, as evidenced by all of the bolt failures.

I respectfully suggest that your scenarios belie a lack of understanding of modern manufacturing procedures and overlook best-practices implemented by competent repair personnel. Yes, any mode of assembly failure is possible but modern manufacturing processes are designed to reduce those possibilities to an absolute minimum and are proven to be quite successful in that regard.

Insofar as techniques for achieving design fastener torque, I suggest your proclamation of what's "PROPER" may be misguided. You may find this article of interest. In that article (see "SPECIAL TORQUE SETTINGS") there's a brief discussion about the reason and advantages of a 'torque plus turn' specification. This is a general-audience article, the topic can be explored in much more technical detail if one chooses to conduct further research.

Again with all due respect, I appreciate your problem-diagnosis efforts but think that you (along with the rest of us posting here) lack both the forensic data and the engineering expertise to derive any meaningful conclusions in regard to this matter. Though manifesting in the failure of a bolt I suspect the root cause and 'solution' involves more than that fastener (my own bit of data and expertise-limited speculation ).

 

[dolsen]

I respectfully suggest that your scenarios belie a lack of understanding of modern manufacturing procedures and overlook best-practices implemented by competent repair personnel. Yes, any mode of assembly failure is possible but modern manufacturing processes are designed to reduce those possibilities to an absolute minimum and are proven to be quite successful in that regard.

Insofar as techniques for achieving design fastener torque, you may find this article of interest. In that article (see "SPECIAL TORQUE SETTINGS") there's a brief discussion about the reason and advantages of a 'torque plus turn' specification. This is a general-audience article, the topic can be explored in much more technical detail if one chooses to conduct further research.

Again with all due respect, I appreciate your problem-diagnosis efforts but think that you (along with the rest of us posting here) lack both the forensic data and the engineering expertise to derive any meaningful conclusions in regard to this matter. Though manifesting in the failure of a bolt I suspect the root cause and 'solution' involves more than that fastener (my own bit of data and expertise-limited speculation).

I worked at KTP for years, until 2019, I’m fairly familiar with what goes on in an assembly plant.

keep in mind there’s a massive difference in the quality of careful work between a general assembly tech and a repair tech. Theres A lot of room for error and many assembly techs will unknowingly or sometimes willingly “follow work instructions to a T” beucase it’a “not their job to inspect the threads” if It’s not on the work instructions

The technology is there to create FANTASTIC world class vehicles, but the give a shit is often lacking

EDIT: after reading your article I think it further vindicates what I am saying. The article states it’s a more accurate method of obtaining torque, which was my argument, BUT it should only be used by engineering to set the parameter for everyone else, not necessarily to say it should be the SOP for large scale assembly ops. That’s more of a TTY method, which is basically what they did, as evidenced by so many bolts yielding

 

[Buyer2021]

I worked at KTP for years, until 2019, I’m fairly familiar with what goes on in an assembly plant.

Then you surely know first-hand that the failure rate attributable to the assembly scenarios you posited in your post are extraordinarily low in consideration of the literally millions of manufacturing steps involved in delivering these high-volume production vehicles. But they do happen and that's why we're thankful for warranties.

The folks and machines on the manufacturing and assembly lines are at the mercy of the designers and engineers behind the product. Methinks (for what that's worth) that's where both the cause and solution to this matter lies.

 

[dolsen]

Then you surely know first-hand that the failure rate attributable to the assembly scenarios you posited in your post are extraordinarily low in consideration of the literally millions of manufacturing steps involved in delivering these high-volume production vehicles. But they do happen and that's why we're thankful for warranties.

The folks and machines on the manufacturing and assembly lines are at the mercy of the designers and engineers behind the product. Methinks (for what that's worth) that's where both the cause and solution to this matter lies.

I understand fully the failure rate of what I’m suggesting, and I still stand by it.

your second statement is partially true, but unfortunately the customers are just as much at the mercy of the assemblers as the assemblers are to the engineers and designers. I promise you that improper assembly is sometimes intentional. Sometimes the assemblers are pissed off, sometimes they’re just a piece of shit.

Let me be very clear though. Well over 99% of the union employees are fantastic people that work hard and want to put out a good product, but when that less than 1% shows their ass and they have a hand in assembling 600+ units per shift, and what they’re doing isn’t caught for a couple shifts, that’s a fuck load of trucks affected.

On the other side of it, many times engineers screw up too, and I’m still betting that it was improper grade bolt used because its obvious that these bolts are being torqued just shy of their failure point

I do completely agree with your final sentence though. I’m simply suggesting there could be other issues exaggerating the failures.

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