Rear axle bolt failure...AGAIN!!

[snapper9601]

Attachment II says if one side is bad replace both if I read it correctly.

Feeling OP's frustration. I wonder what the "as required" means at the end of the first sentence. Does that mean if both bolts are broken?
Right under SERVICE ACTION bullet points
" Dealers are to inspect for a loose or separated wheel end hub bolt and replace both the right hand (RH) and left hard (LH) rear axle half-shaft and hub assemblies as required. This service must be performed on all affected vehicles at no charge to the vehicle owner "

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[jmargo]

Feeling OP's frustration. I wonder what the "as required" means at the end of the first sentence. Does that mean if both bolts are broken?
Right under SERVICE ACTION bullet points
" Dealers are to inspect for a loose or separated wheel end hub bolt and replace both the right hand (RH) and left hard (LH) rear axle half-shaft and hub assemblies as required. This service must be performed on all affected vehicles at no charge to the vehicle owner "

I was looking more specifically at " Description – If one side is broken, order and replace both RH and LH Rear Axle Shafts in one dealer visit"

 

[snapper9601]

I was looking more specifically at " Description – If one side is broken, order and replace both RH and LH Rear Axle Shafts in one dealer visit"

Ah yes, I missed that. Question answered. Full circle to OP's frustration.

 

[Buyer2021]

I was looking more specifically at " Description – If one side is broken, order and replace both RH and LH Rear Axle Shafts in one dealer visit"

Good point which I failed to note, upon more careful reading IMO that's further reinforced by this text in the Labor Allowances section of the CSP:

Remove rear tires and inspect for broken axle bolt. If at​

least one is broken, replace both rear axle and hub​

assemblies, install rear tires. Includes axle fluid check and​

top off.​

​

One thing perhaps worth noting IF Ford is playing hardball ... the CSP list of "Affected Vehicles" covers a limited build-date-range ending September 30, 2021. I suppose it's possible that Ford could assert that failures falling outside of that date-range are not covered by the terms of the CSP but are covered by the different terms of the OE powertrain warranty (e.g. repairs are made only when parts actually fail).

FWIW on the table of bolt failures I'm maintaining on the other forum, 37% of those reporting build-dates are after September 30, 2021.

 

[fordhouston]

another excuse for me to get rid of my truck before it occurs.. lol

 

[Snakebitten]

A forum will give you a 1000 reasons to get rid of a perfectly functioning truck.

 

[UGADawg96]

FWIW on the table I'm maintaining on the other forum, 37% of those reporting build-dates are after September 30, 2021.

I am a Nov 21 build and my driver's side sheared.

 

[HammaMan]

another excuse for me to get rid of my truck before it occurs.. lol

Personally I'd just buy the bolts and swap them myself if I was subject to the issue. Granted my engine choice comes with the upgraded springs and cooling of the max tow w/ out the axle assembly, that has thus far, shown no tangible benefit. On the PB's, the only thing the max tow does is decrease the payload, which is already the limiting factor for the trucks. Not that I'd really want to tow more than 11klbs any appreciable distance with the platform.

 

[Buyer2021]

another excuse for me to get rid of my truck before it occurs.. lol

I guess folks gotta do what they gotta do and exercise their own prerogatives.

Myself, I'm not looking for an excuse, I'm just too damned happy with my Max Tow 2022 Lariat SuperCab. For me there's simply is no comparable replacement. I'm gonna keep riding this out with the optimistic view that Ford will, eventually, remedy this concern and I'll be happy for the remaining 18+ years of ownership like I've enjoyed with my 2005 XLT.

No worries!

 

[fordhouston]

Ford will, eventually, remedy this concern

yeahhhhh i don’t know about that one.. lol

 

[fordhouston]

Personally I'd just buy the bolts and swap them myself if I was subject to the issue. Granted my engine choice comes with the upgraded springs and cooling of the max tow w/ out the axle assembly, that has thus far, shown no tangible benefit. On the PB's, the only thing the max tow does is decrease the payload, which is already the limiting factor for the trucks. Not that I'd really want to tow more than 11klbs any appreciable distance with the platform.

a user on here did that and still had his bolt(s) sheer. i read but can’t remember which thread it was exactly lol

 

[RidingHighNCO]

Take care lest you get 'flamed' - the word "shear" to describe this failure is a hot-button no-no for some forum pundits

FWIW, based on closely following many threads about this and study of the Workshop Manual .....

• Most failures are discovered when folks have a rear wheel removed for whatever reason (tire rotation being common, for example)
• The owner has no idea how long they've been driving with a broken bolt
• The broken bolt/washer will be retained inside the center 'hubcap' of the wheel until the wheel (or the center logo cap) is removed
• As mentioned, the easiest 'inspection' is to pop-off the logo center cap on the wheel and look inside
• Sometimes the bolt tumbles inside that space and can be heard as clicking / tapping / rattling sound; sometimes it may wedge in one place and not tumble / not cause a noise
• Often the broken bolt end is 'well-peened' (see the pic in post #25 above) indicating that it's been tumbling around in there for some time (a 'fresh break' will have some sharp edges at the very end of the break)
• I've read a very few anecdotes (like ~3 out of well over 100) where the owner has suffered loss of driving force at the axle; those are cases where apparently many miles accumulated after the break and the axle shaft slowly migrated inboard from the hub until the splines disengaged or failed due to reduced engagement depth; none of these reported damage inside the differential as a result of that inboard migration. Otherwise, I've not seen any reports of drive-ability issues.
• NOTE that the wheel is not retained by this bolt, nor is the brake rotor, nor does the brake rotor / caliper play a role in retaining the wheel even with the bolt broken. The wheel and brake rotor are retained by the hub flange which is integral to the hub itself, the hub being bolted to the axle housing by 4 bolts independent of the axle shaft.
• NOTE too, that unlike all other current F150 axles, this unique 3/4-float axle assembly does not have a retaining circlip inside the differential which must be removed to extract the axle shaft; the complete assembly is removed without need to remove the differential cover

Attached FYI is the wheel hub R&R procedure which shows the 'assembly'; when the repair is done as specified in the CSP previously posted, the part number for the 'assembly' includes the axle shaft with the hub pre-installed on the shaft and bolted as a complete unit. The installing dealer does not need to press the hub on the axle shaft or install the end bolt, that's already done, they just pull out the complete assembly and re-insert the complete replacement assembly.

IMO this is a good procedure for the repair in that IF there has been any damage to the splined interface between the axle shaft and the hub, or IF there's any damage to the bearing(s) in the hub, that's all replaced as a pre-assembled unit provided to the dealer service tech.

Yes, to date the replacement assembly is the same PN and apparently the same parts as OE; so IF the failure was due to a 'bad batch' of out-of-spec parts, presumably the replacement is a cure; BUT IF the root cause is some deeper design flaw, at least for now that is not cured it seems. Ford has not explicitly publicly revealed the underlying cause of the failures to this point in time (if they even know that for certain themselves).

(there are of course countless posts by forum experts each claiming that they know the root cause of the failure and professing the certain solution ranging from different bolt-torque to installation of mega-strength bolts to total axle redesign; I guess ya gotta run with whatever makes ya feel good )

FWIW here's my best effort at a schematic diagram of the subject axle main components
View attachment 83073
NOTE - Ford considers the hub a 'non-serviceable' unit (to be replaced in its entirety if damaged) so the Workshop Manual reveals nothing about the internals / bearing(s) configuration within the hub.

Thank you for this info, this answers many of my questions.

 

[WhiteLightningnshitshadow]

This is one of those things Ford is aware of, but can't likely do anything about because there simply isn't a suitable fix yet. What it likely needs is a slight redesign of the axle and a recall to swap it out entirely. There's too much stress hitting that bolt. A new bolt doesn't make it less likely to occur as I've seen at least 3 different cases now where replacements have failed.

One of the rare design issues. Being a little quicker to address the problem would be a good decision made at the executive level.

 

[Snakebitten]

But wouldn't that mean it's NOT a batch issue and we should see equal percentage of bolt failures for every model year and build date?

 

[HammaMan]

What grade bolt are they using? 10?

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