Can anyone tell me what this is (part failure on axle)......?

[Rusty]

Another truck - mine - has fallen into the sheared off bolt category. Took it in for an oil change and they discovered it then. Said it could take 3 months...as that's how long the last one took. They are paying for a rental for me. (no loaners) Super disappointed. And concerned about it happening again once it's "fixed". As I don't think Ford really knows how to fix the problem....besides just replacing the parts.

Sponsored

 

[AndrewMC]

Took it to the dealer, it's been really wet the past couple days here and noticed it went away and told them they're probably going to not be able to duplicate it... and sure enough they weren't able to... We'll see what's the next play here.

Update to the update: Squeak returned, pulled into dealer right away, they took it for a ride and confirmed they hear it. They "aren't sure why the bolt sheared in the first place" so they're "tearing it apart". I'm in a hybrid Escape loaner now that someone clearly has smoked in at one point and tried to mask with chemicals... smells awful in this thing. 35-40mpg is kinda nice though.

 

[mhorse]

I wonder if the bolt itself is at fault or is there stress inside the axle that causes the bolt to fail. If I remember from all the posts, the passenger side seems to be a common denominator . Also, why replace the entire axle assembly when it should be possible to just replace the bolt. There seems to be more to this than just a failing bolt.

Here's my take... My OPINION... take it FWIW.

I just joined this forum, as I'm seeing this problem myself... and I have experience with this type of assembly issue in other machinery, vehicles and powersports equipment.

I believe it's actually a simple, engineering mistake on the part of Ford. Inability to provide sufficient preload over a sufficient length of fastener to be resistant, enough, to the cyclic fatigue happening with this axle retention setup

From my view, it's common issue on splined axle drive assembly retainers ... The bolt is threaded all the way to the head (or almost)... and the washer, though it is 'thick' compared to must hardware-store washers, is not thick enough to allow for much stretch in the bolt (aka preload).

Long term/factory solution... The bolt should be longer, with about a 20mm non-threaded section under the head... and a section of non-threaded counterbore inside the axle to allow for the bolts "shoulder" to be preloaded (stretched) the correct amount, at the proper torque spec for that bolt.... and this will provide enough elasticity to the assembly and relieve the fatigue issue.

It's not an issue of the bolt not being strong enough... it is that there is no real way to preload the bolt over a sufficient length. This is in addition to the bolt being threaded all the way to the highest stress point for the assembly.

The remedial fix I'll be trying ...I have my machinist buddy make a MUCH thicker steel washer/spacer for under the bolt head... say 20mm-25mm thick and use that instead of the current washer. (so long as it fits under the center cap of the wheel)

Replace the factory bolt with a high quality bolt (not a harder bolt) max of a grade 10.9 ... ARP has as a good selection of these, much better quality than Ford can afford to use for the most part.... with a good amount of unthreaded section directly under the head... but less thickness than the new spacer... This bolt would have the same amount of thread engagement in the axle itself.

Torque the bolt to spec... and the issue of this broken bolt should go away.

Here is a decent, easy to understand, presentation of Preload from ARP:

It is a fundamental engineering concept that the force in a bolt in an ideal preloaded joint will remain equal to the preload until the externally applied force exceeds the preload. Then the force in the bolt will be equal to the external force.

This means that fluctuating external forces will not cause fluctuating forces in a preloaded bolt as long as the preload exceeds the external force.

The result is that fatigue failure will not occur.

All this being said... I believe there is NO dealership out there that would apply this remedy unless it was an "official" solution provided in a TSB or Recall... using Ford branded replacement parts.

I guess we'll see how the 2023 or maybe 2024 axles are assembled and what parts are used to replace these on the the newer factory builds... this will give a much better idea of the cause of the issue.

















.

 

[AndrewMC]

Here's my take... My OPINION... take it FWIW.

I just joined this forum, as I'm seeing this problem myself... and I have experience with this type of assembly issue in other machinery, vehicles and powersports equipment.

I believe it's actually a simple, engineering mistake on the part of Ford. Inability to provide sufficient preload over a sufficient length of fastener to be resistant, enough, to the cyclic fatigue happening with this axle retention setup

From my view, it's common issue on splined axle drive assembly retainers ... The bolt is threaded all the way to the head (or almost)... and the washer, though it is 'thick' compared to must hardware-store washers, is not thick enough to allow for much stretch in the bolt (aka preload).

Long term/factory solution... The bolt should be longer, with about a 20mm non-threaded section under the head... and a section of non-threaded counterbore inside the axle to allow for the bolts "shoulder" to be preloaded (stretched) the correct amount, at the proper torque spec for that bolt.... and this will provide enough elasticity to the assembly and relieve the fatigue issue.

It's not an issue of the bolt not being strong enough... it is that there is no real way to preload the bolt over a sufficient length. This is in addition to the bolt being threaded all the way to the highest stress point for the assembly.

The remedial fix I'll be trying ...I have my machinist buddy make a MUCH thicker steel washer/spacer for under the bolt head... say 20mm-25mm thick and use that instead of the current washer. (so long as it fits under the center cap of the wheel)

Replace the factory bolt with a high quality bolt (not a harder bolt) max of a grade 10.9 ... ARP has as a good selection of these, much better quality than Ford can afford to use for the most part.... with a good amount of unthreaded section directly under the head... but less thickness than the new spacer... This bolt would have the same amount of thread engagement in the axle itself.

Torque the bolt to spec... and the issue of this broken bolt should go away.

Here is a decent, easy to understand, presentation of Preload from ARP:





All this being said... I believe there is NO dealership out there that would apply this remedy unless it was an "official" solution provided in a TSB or Recall... using Ford branded replacement parts.

I guess we'll see how the 2023 or maybe 2024 axles are assembled and what parts are used to replace these on the the newer factory builds... this will give a much better idea of the cause of the issue.

















.

Nice writeup on this... I'm somewhat concerned that when "techline" gets back with the dealer my PB is at they won't have a true solution....

 

[notabot]

The remedial fix I'll be trying ...I have my machinist buddy make a MUCH thicker steel washer/spacer for under the bolt head... say 20mm-25mm thick and use that instead of the current washer. (so long as it fits under the center cap of the wheel)

Replace the factory bolt with a high quality bolt (not a harder bolt) max of a grade 10.9 ... ARP has as a good selection of these, much better quality than Ford can afford to use for the most part.... with a good amount of unthreaded section directly under the head... but less thickness than the new spacer... This bolt would have the same amount of thread engagement in the axle itself.

Torque the bolt to spec... and the issue of this broken bolt should go away.

I dig it!

 

[SuperRaptor]

I have a long road trip coming up, does anyone think it would be a good idea to replace these bolts before the trip?

 

[AndrewMC]

New axle coming for me after a second bolt broke. Unknown ETA. Yaaaay

 

[notabot]

I have a long road trip coming up, does anyone think it would be a good idea to replace these bolts before the trip?

The kicker is, as I see it, with some off-the-cuff, pseudo-brainiac thinking:
What do you replace them with?
MHorse had a thinking cap on when positing his theory and remedy.
If they haven't failed, you might have one of the "good ones". Should you mess with it?
If you do mess with it and it fails, will Ford still warranty it or will they give you a hassle?
If you replace it with a stock bolt, what have you gained?

 

[AndrewMC]

The kicker is, as I see it, with some off-the-cuff, pseudo-brainiac thinking:
What do you replace them with?
MHorse had a thinking cap on when positing his theory and remedy.
If they haven't failed, you might have one of the "good ones". Should you mess with it?
If you do mess with it and it fails, will Ford still warranty it or will they give you a hassle?
If you replace it with a stock bolt, what have you gained?

I'll add, the dealer replaced my broken bolt with a stock one and it broke again, so I'm waiting for an axle

 

[AndrewMC]

New axle arrived sooner than I was expecting. Got a call from the dealer earlier expecting to hear some wild and crazy lead time, and to my surprise they were done! Just curious, do we have any evidence of an axle replacement NOT fixing the problem, or have we seen axle replacements solve this issue? Has anyone determined what ultimately was going on here?

 

[woodworker73]

I just brought my 2021 F150 PB with max tow axle in for a routine oil change, tire rotation and NY state inspection on 10/08/22 with 19,700 K. The service manager called and told me my truck was not safe to drive and that the axle bolt on my rear axle had sheared off and that more than likely I had been driving with it like this for awhile due to the evidence of some rust on the bolt. I was told that he emergency ordered a bolt and should have it in some time this week.

The service manager showed me the bolt which looks ridiculously undersized in my opinion (not an engineer) that sheered off. He said he was only ordering the bolt, and after reading the comments on here it sounds like the entire axle should be replaced? I am to say the least a little more than concerned about this. I mean, even he made the comment that it was a stupid design on Fords part (he's isn't an engineer either). My big concern here is that Ford doesn't seem to know exactly what the issue is, which is way scary. How do you definitively fix something without knowing what is causing the problem?

Has anyone had this corrected yet? And if so is it fine now or have you had the issue again?

The dealership loaned me an eco sport (new) which is the biggest POS I have driven in awhile, not to mentioned I look ridiculous in it, lol.

I will be filing a complaint with the NHTSA tomorrow and would suggest and ask anyone with this issue to do the same. This is my first Ford truck in many years(coming from GM) and this is a huge Bummer! I mean I went from loving the truck to being sick to my stomach not knowing if its going to kill me, someone I love (even worse) or someone else on the highway. Comments or answers to the questions I've posted would be appreciated. Thank you.

 

[Ford Motor Company]

Hi Jim.

I just brought my 2021 F150 PB with max tow axle in for a routine oil change, tire rotation and NY state inspection on 10/08/22 with 19,700 K. The service manager called and told me my truck was not safe to drive and that the axle bolt on my rear axle had sheared off and that more than likely I had been driving with it like this for awhile due to the evidence of some rust on the bolt. I was told that he emergency ordered a bolt and should have it in some time this week.

The service manager showed me the bolt which looks ridiculously undersized in my opinion (not an engineer) that sheered off. He said he was only ordering the bolt, and after reading the comments on here it sounds like the entire axle should be replaced? I am to say the least a little more than concerned about this. I mean, even he made the comment that it was a stupid design on Fords part (he's isn't an engineer either). My big concern here is that Ford doesn't seem to know exactly what the issue is, which is way scary. How do you definitively fix something without knowing what is causing the problem?

Has anyone had this corrected yet? And if so is it fine now or have you had the issue again?

The dealership loaned me an eco sport (new) which is the biggest POS I have driven in awhile, not to mentioned I look ridiculous in it, lol.

I will be filing a complaint with the NHTSA tomorrow and would suggest and ask anyone with this issue to do the same. This is my first Ford truck in many years(coming from GM) and this is a huge Bummer! I mean I went from loving the truck to being sick to my stomach not knowing if its going to kill me, someone I love (even worse) or someone else on the highway. Comments or answers to the questions I've posted would be appreciated. Thank you.

Hi Jim. Can you send us a DM with your VIN and dealership info? I can look into this for you.

 

[rb304]

My truck was towed from my house last night to the dealership for the SAME issue. I have a '21 F150 XL, Max Tow, 3.73 locking rear diff. @Ford Motor Company when will the TSB come out for this, or potentially a recall? I have also filed a complaint with NHTSA about this issue. I will be confirming with the dealership Monday that they will be inspecting and replacing both sides. Thankfully I was not stranded due to this issue. I will give credit where credit is due, it was fantastic to request roadside service from the FordPass app, and they were here within an hour to pick it up. You know, Ford, vehicle immobilization is usually to prevent thefts, not prevent owners from driving.....

 

[notabot]

Thankfully I was not stranded due to this issue. I will give credit where credit is due, it was fantastic to request roadside service from the FordPass app, and they were here within an hour to pick it up. You know, Ford, vehicle immobilization is usually to prevent thefts, not prevent owners from driving.....

Hey @rb304 , sorry to hear you're another owner affected by this issue. Are you saying the call through the FordPass app for a tow immobilized the truck?

 

[rb304]

Hey @rb304 , sorry to hear you're another owner affected by this issue. Are you saying the call through the FordPass app for a tow immobilized the truck?

hi @notabot,
Good clarifying question - No, using the app did not immobilize the truck, the bolt shearing off did. It was more of a facetious comment because the bolt breaking renders the truck unsafe to drive.

Sponsored