Looks like another axle bolt shear…

[RossRR]

Add me to the list. It's a 2021 Powerboost with Max Tow. Really sucks because I need my truck to tow my car this weekend and they're saying they can't even look at it for a week. Another event down the drain thanks to something breaking.

Well, you could go ahead and tow your car...you can still drive the truck and Ford hasn't issued a safety recall so it can't be too serious of a failure mode.

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[b4hand]

Well, you could go ahead and tow your car...you can still drive the truck and Ford hasn't issued a safety recall so it can't be too serious of a failure mode.

That's the thing. The dealer was making it seem like the axle will fall out if I drive it, but they can't hold it if it isn't a recall correct?

 

[RossRR]

That's the thing. The dealer was making it seem like the axle will fall out if I drive it, but they can't hold it if it isn't a recall correct?

Well, I don't know the legalities involved regarding continuing to drive the vehicle after reporting a failed part to the dealer. There might be something in the contract you signed when you bought it but who reads through all those details?

Some folks have reported that they actually lost drive to the rear wheels after driving with the broken bolt, but it may have been thousands of miles before the axle worked its way loose. Who knows?

Just curious if you went on the NHTSA website and filed a safety failure report on your vehicle. The more that are filed, the more pressure on Ford to issue a recall...

https://www.nhtsa.gov/report-a-safety-problem#index

 

[SumGuy]

I specifically emailed my service advisor asking about the safety of driving with the broken bolt.

that way ford was on notice of a potential safety issue. If anything happened with my kids in the car due to fords incompetence, I wanted to have written documentation from the dealer stating the vehicle was safe, or not, to drive.

first is safety of my family, and if anything did happen, I would own my own dealership network.

why ford is apparently pinching pennies with safety is beyond me. Use a better grade bolt! What would that be….an extra $1 per bolt?

CYA: allegedly.

 

[Buyer2021]

Since the bolt places tensile tension on the axle (as in it's trying to pull the axle out), there's probably a beefy C clip in the pumpkin like traditional style axles have.

Examination of the pertinent Workshop Manual R&R procedures makes it explicitly clear that there is no C-clip on the inboard end of the 3/4-float axle shaft. The axle shaft is removed from the housing without accessing the inside of the differential at all.

If that bolt was the ONLY thing holding the wheel on, it'd be an emergency DO NOT DRIVE recall situation.

The wheel (and brake disk) mounts to the wheel flange (with wheel studs pressed through that flange from the back) which is integral to the sealed (non-serviceable) Wheel Hub Assembly; the Wheel Hub Assembly is bolted (4 bolts) to the axle housing. It is the Wheel Hub Assembly which 'holds the wheel to the vehicle', not the single axle end-bolt.

Note that the internal rotating components of the Wheel Hub Assembly (the bearing inner races) may be 'squeezed' between the inboard lip/washer on the axle shaft and the outboard end bolt/washer. The R&R procedure calls for the Wheel Hub Assembly to be hydraulic-pressed 'home' against that lip/washer on the axle shaft. The single axle end bolt may serve, in part, to impose a design 'pre-load' on the bearings in the Wheel Hub Assembly, though that function is not stated in the Workshop Manual.

 

[HammaMan]

...

Removed the post -- only room for accurate info here

The bolt is even more worthless than I assumed. Is it twin balls, a combo ball needle, or is there a thrust bearing? I couldn't see any reason for the compression unless it's a combo thrust bearing arrangement -- possibly even twins?

 

[Buyer2021]

Is it twin balls, a combo ball needle, or is there a thrust bearing? I couldn't see any reason for the compression unless it's a combo thrust bearing arrangement -- possibly even twins?

In regard to the internals of the Wheel Hub Assembly on this specific 3/4-float axle application, Ford has not elected to enlighten us with any definitive information. This is typical of assemblies which are intended to be serviced by total replacement (there's no detailed service procedure in the Workshop Manual for the bearing(s) in that assembly, whatever they may be).

Some sources have posted 'cross-section diagrams' of other / 'typical' floating axle bearing assemblies, but none of those claim to be accurate to this specific application / hub assembly configuration, they're just speculation in that regard.

Until someone gets hold of a Gen 14 3/4-float rear wheel hub assembly and dissects the SOB, we don't know with any certainty what's in there in the way of bearings, etc.

That's why I carefully caveat my statements about a pre-load function as "may" and carefully disclose that's not stated in the Workshop Manual - I do not know that to be the case.

I'll note that it's quite common for tapered roller bearings, which can serve to carry both perpendicular and axial thrust loads, to be 'pre-loaded' installations based on torque or 'turns' of a 'squeezing' fastener. Again, I don't know that to be the case here.

 

[hotrodmex]

In regard to the internals of the Wheel Hub Assembly on this specific 3/4-float axle application, Ford has not elected to enlighten us with any definitive information.

I'll note that it's quite common for tapered roller bearings,

I can't tell if you're speculative of them being tapered roller, as it's listed in the e-source spec doc, or not.

 

[{tpc}]

Looks like the correct thread to add this to. I checked the axle bolts on mine the other day and they are still intact. 18k miles *knock on wood*

 

[islandboy47]

My '21 PB is currently at the dealership for another issue and maintenance and I asked them to look for any TSB's on the max tow axle bolt issue and they called and left a voicemail asking what I was talking about because they can't find anything. I haven't had any issues yet, but wanted to see if there was anything preventative that can be done. Anyone have something I can forward over to them or any experience yet with fixing this problem before it breaks? I do tow and would rather not wait until it breaks, but figured just pointing them to a forum online wouldn't be enough for them to actually do anything lol.

 

[Buyer2021]

Just FYI / FWIW, I've just updated the tabulation of broken bolts reported on 'the other forum'.

An admittedly limited sampling pool (data tabulated ONLY from reports on that specific forum thread) but still of interest IMO ...

• 96 unique owners reporting with a growing number of 'now the other side' failures (which are noted but not counted in the tabulation).
• Over 80% are 2021 model year when one considers second failures.
• PowerBoost predominates at 65+% of the affected
• Still no reports in that forum thread for a failure on a build after May 2022***.

***IMO this is suggesting that the issue was 'resolved' on later builds as some those have surely accumulated significant miles by now. Given no evidence of a part number or design change, perhaps indeed it was bad parts batch(es) or improper assembly procedure at the factory (Note: speculation!).

OR, maybe I'm too optimistic / we're just missing part of the affected population in that limited reporting pool.


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[Northguy]

Just FYI / FWIW, I've just updated the tabulation of broken bolts reported on 'the other forum'.

An admittedly limited sampling pool (data tabulated ONLY from reports on that specific forum thread) but still of interest IMO ...

• 96 unique owners reporting with a growing number of 'now the other side' failures (which are noted but not counted in the tabulation).
• Over 80% are 2021 model year when one considers second failures.
• PowerBoost predominates at 65+% of the affected
• Still no reports in that forum thread for a failure on a build after May 2022***.

***IMO this is suggesting that the issue was 'resolved' on later builds as some those have surely accumulated significant miles by now. Given no evidence of a part number or design change, perhaps indeed it was bad parts batch(es) or improper assembly procedure at the factory (Note: speculation!).

OR, maybe I'm too optimistic / we're just missing part of the affected population in that limited reporting pool.


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Thanks for this. As someone with a June build 2022 max tow non PB, I am hopeful you are right about the issue being resolved.

 

[Snakebitten]

I'm an April 2022 build.
A month early for @Buyer2021 's fence date. I also already have a set of spare bolts on hand.

I just haven't convinced myself whether I should replace the factory bolts yet.
One reason is that I'm kind of hoping the truck IS beyond the proverbial "bad batch"
And second, I'm less than 100% sure of the proper torquing technique.

I do know that I will probably kick myself if one of them does snap and I hadn't replaced it beforehand, which is likely a lot easier to do.

 

[Buyer2021]

I do know that I will probably kick myself if one of them does snap and I hadn't replaced it beforehand, which is likely a lot easier to do.

IMO the effort is the same if done 'right', here's why ...

• When you do a 'pre-emptive' replacement without pulling the axle-shaft+hub assembly, you have no way of knowing if your bolt is already starting to 'back out' or 'stretch'.
• We don't know if or how much displacement may or may not have an adverse effect on the wheel hub / bearing internals.
• The only way to know is by pulling the complete assembly and ensuring that the hub is pressed-home against the axle-shaft 'lip / inboard washer' using a hydraulic press as specified in the previously posted R&R procedure.

Personally, IF your truck is one of the problematic builds, I think that pre-emptive replacement of only the bolt in-situ without conducting the full R&R procedure is at best a delaying tactic, not a long-term strategy for solution (particularly IF the problem is with some part-tolerance other than the bolt itself, such as the shaft/hub spline interface). And if your truck is not one of the problematic builds, it invites unnecessary risk.

But hey, that's just one idiot's considered opinion, recognizing that we still don't really know what's going on, "YMMV"! .

 

[turbopilot]

I'm an April 2022 build.
A month early for @Buyer2021 's fence date. I also already have a set of spare bolts on hand.

I just haven't convinced myself whether I should replace the factory bolts yet.
One reason is that I'm kind of hoping the truck IS beyond the proverbial "bad batch"
And second, I'm less than 100% sure of the proper torquing technique.

I do know that I will probably kick myself if one of them does snap and I hadn't replaced it beforehand, which is likely a lot easier to do.

Do you have the part number for this bolt? Thanks.

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