F150 Powerboost Axle bolt sheared off

[unafFORDableXLT]

Yup, I’ve got the locker and 3.5 EB.
I guess I’ve been lucky so far. About 14k miles. No noise and I’ve pulled the center caps to inspect.
I’ve towed my travel trailer cross country, from Maryland to the Oregon coast, and from Portland to San Diego and back. No issues other than the usual “Trailer Disconnected” warning while driving. Even the trailer brakes and wipers work!

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[UGADawg96]

Update... service called me back. They can see it on 12/2 and already have a loaner/rental on hold for me. And that works since I'm leaving town Friday for work for a week and get back on 12/1.

 

[Snakebitten]

Wow. Wonder what changed their tune?
That's great news considering.

 

[Buyer2021]

I guess I’ve been lucky so far. About 14k miles. No noise and I’ve pulled the center caps to inspect.

You're far from alone.

Even though forums don't reflect the entire owner population they do tend to be magnets for reports of this sort of problem (particularly when dealer remedy takes a long time as is typical in this case) and based on that IMO it's safe to conclude that this failure has afflicted only a very small fraction of all Gen 14 MAX tow vehicles on the road.

Take a look at this informal 'tally' which I update regularly in a forum thread on this topic with 624 posts to date. ​

I've no idea WHY, and IMO that in no way excuses Ford's lack of published response to the issue (not even a TSB or SSB), however rare it may be.

 

[UGADawg96]

Wow. Wonder what changed their tune?
That's great news considering.

I was softly persuasive.

 

[tony72cutlass's']

Those mechanics, I guess, are long retired old men?

We’re old, cranky, and thinking about ordering 20 dozen axle bolts and starting a bolt replacement side hussle in our driveway

 

[Mosey]

Add me to the list. Rotated tires and this fell out of the right rear wheel. My build date was in September 2021. 2021 PB SCREW XLT w/max tow package. Service manager can’t get me in for four weeks to diagnose the issue even with me holding the bolt in my hand.

PS: submitted NHSTB compliant.

 

[Buyer2021]

Add me to the list.

IF referring to this list as opposed to 'the list in general', you'll need to make a post in that forum thread (which would be most appreciated!).

Due to risk of different user-names causing redundant entries I'm making no attempt to track failure reports between different forum threads (It's a basic data integrity issue).

 

[Mosey]

IF referring to this list as opposed to 'the list in general', you'll need to make a post in that forum thread (which would be most appreciated!).

Due to risk of different user-names causing redundant entries I'm making no attempt to track failure reports between different forum threads (It's a basic data integrity issue).

Just “the list in general”.

 

[dolsen]

Ford has been silent on this topic. The axle and bolt appear to have the same part# as ever, so the only possible change is installation torque at the factory. But that too is unknown.

Can anyone post a pic of the sheared face of the bolt? This should give some clue as the the failure mode (porosity or a clean shear would likely indicate weak material or poor manufacturing practices, AKA bad bolt, necking would indicate over tightening, AKA improper assembly)

 

[alkoser]

Can anyone post a pic of the sheared face of the bolt? This should give some clue as the the failure mode (porosity or a clean shear would likely indicate weak material or poor manufacturing practices, AKA bad bolt, necking would indicate over tightening, AKA improper assembly)

Theres about a thousand pics on the other f150 forum in this thread 2021 Powerboost Rear Rotor/Axle Bolt Sheared - Ford F150 Forum - Community of Ford Truck Fans

 

[dolsen]

Theres about a thousand pics on the other f150 forum in this thread 2021 Powerboost Rear Rotor/Axle Bolt Sheared - Ford F150 Forum - Community of Ford Truck Fans

They seem to all universally show necking.

 

[Porpoise Hork]

Ford did release updated torque specs for the stretch bolts. 52 ft/lbs + 90 degree turn. I replaced mine and found that to complete the 90 turn the final torque is 120 ft/lbs. So it's very possible they were over torqued which could produce the necking and subsequent failures.

 

[Handle]

Ford did release updated torque specs for the stretch bolts. 52 ft/lbs + 90 degree turn. I replaced mine and found that to complete the 90 turn the final torque is 120 ft/lbs. So it's very possible they were over torqued which could produce the necking and subsequent failures.

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.

 

[dolsen]

Ford did release updated torque specs for the stretch bolts. 52 ft/lbs + 90 degree turn. I replaced mine and found that to complete the 90 turn the final torque is 120 ft/lbs. So it's very possible they were over torqued which could produce the necking and subsequent failures.

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

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