F150 Powerboost Axle bolt sheared off

[hotrodmex]

There are 3 different rears on the F150, standard, max tow 3/4 floating & the heavy duty.

If you mean the 8.8 (Does anyone still get that?), the 9.75, and the 9.75 HD-3/4 float, then there are 3.

There are not three 9.75 axles in the current model year.

If you are referring to the old 9.75 HD (pre-21) that was not 3/4 float but used thicker axles, then ok...but you should probably then use the complete names for clarity.

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[AnthonyE]

One way to tell HD 3/4" float axle from normal 9.75 axle: HD has four additional bolts on the larger axle endcap for holding on the hub and bearing, along with the two brake caliper bolts. STD ends in a small flange with just the brake caliper bolts.

That's a good point, I don't think I've seen this from someone EB or 5.0 with MaxTow. Do PB come from only one of the factories, or both?

Hello - My 2021 Lariat has a 3.5 engine with echoboost and max tow package. The rear passenger bolt broke off around 13k to 14k miles. I have been waiting a few weeks for the dealership to look at it and find a root cause.

It turns out that 2 dealerships in my area claim they have NOT seen this issue!!! They told me however, that it is safe to drive around town, but I should not travel with it out of town!! We need FMC to take ownership of the problem ASAP.

 

[Ntsi]

They told me however, that it is safe to drive around town, but I should not travel with it out of town!!

I think I would find another dealership ASAP! They are right that you won’t lose you wheel, so it is kinda safe, but the Axel is not held into the hub anymore. It can back out, and what would happen if it fell out of the hub? Destroyed Axel, possible rear end.. and what if it hit the road while driving at speed? Could cause a serious accident. And since it is not held into the hub, as it backs out, it will destroy the hub My dealership wouldn’t even let it out of their shop when they saw the issue.

Since this is a warranty issue, they should be able to get you a loaner car while they work it out with FMC.

when mine broke, they had to replace the Axel and hub due to the damage caused to the spines in the hub.

 

[Pedaldude]

Since Ford is generally having the dealerships replace the entire hub/axle assembly. I don’t think any extra harm would likely come from the hub bolt being missing.

The hub assembly is still held on by the brake disc and brake caliper. From what I understand, the only harm is accelerated wear to the press fit splines and the hub seals and bearings.

Many of the people that have had this issue don’t even know how long the bolt was broken and only discovered it when rotating the tires.

If these trucks had drum brakes, it would be an entirely different story and I would bet that entire wheels/hubs would have already seperated fully from at least one truck.

I kind of think that saying you can drive the truck but not on the highway is a bit of an under reaction and not even driving it out of the shop is an over reaction.

 

[AndrewMC]

Since Ford is generally having the dealerships replace the entire hub/axle assembly. I don’t think any extra harm would likely come from the hub bolt being missing.

The hub assembly is still held on by the brake disc and brake caliper. From what I understand, the only harm is accelerated wear to the press fit splines and the hub seals and bearings.

Many of the people that have had this issue don’t even know how long the bolt was broken and only discovered it when rotating the tires.

If these trucks had drum brakes, it would be an entirely different story and I would bet that entire wheels/hubs would have already seperated fully from at least one truck.

I kind of think that saying you can drive the truck but not on the highway is a bit of an under reaction and not even driving it out of the shop is an over reaction.

Based on my experience it seems like they are only going to this step if they can't get the bolt out. They were able to get the bolt out on mine, chased the threads and installed a new bolt.

 

[Pedaldude]

I was wondering that earlier; if that’s the case, it seems Ford dealerships are pretty lousy at removing broken bolts. Or they’re just not too worried about doing all that extra work on Ford’s dime.

 

[AndrewMC]

I was wondering that earlier; if that’s the case, it seems Ford dealerships are pretty lousy at removing broken bolts. Or they’re just not too worried about doing all that extra work on Ford’s dime.

Where it took it said they had to fight with ford to get them to pay another hour on it. (Rowe Westbrook, Maine)

 

[Ntsi]

Yeah. They didn’t want to remove the broken bolt on mine, because of the spine damage. They ended up replacing the hub and Axel on mine on drivers side. The passwnger side, they had to replace the Axel because the speed sensor blew apart. The magnet part of the sensor is intograted into the Axel and can’t be replaced without changing the Axel.

 

[Pedaldude]

I think at this point, unless there’s a TSB with specific information; the individual dealerships are just winging it and I have little faith in there being much consistency between them and their evaluation of what parts need replacement or not.

My truck needed a slight adjustment of the hinges that a second dealership’s body shop spent a whopping ten minutes of actual wrenching to correct the problem. The first dealership was either so clueless or greedy that they said my truck needed brand new doors and even had the balls to ask Ford to do the work!

This is why it’s so important for Ford to get to the bottom of this and say something. Ten different dealers can have ten different explanations and solutions and it’s hard to know what is correct when they try to keep everyone in the dark.

Service advisors are salespeople first and often don’t know shit about what they’re saying and it’s a game of telephone between them and the technicians who usually have zero respect for the service advisors and have little motivation to explain to them what’s going on.

Also, who knows if the splines and wheel speed sensor were damaged by the parts failure, or by trying to extract the stuck bolt.

 

[AndrewMC]

I think at this point, unless there’s a TSB with specific information; the individual dealerships are just winging it and I have little faith in there being much consistency between them and their evaluation of what parts need replacement or not.

My truck needed a slight adjustment of the hinges that a second dealership’s body shop spent a whopping ten minutes of actual wrenching to correct the problem. The first dealership was either so clueless or greedy that they said my truck needed brand new doors and even had the balls to ask Ford to do the work!

This is why it’s so important for Ford to get to the bottom of this and say something. Ten different dealers can have ten different explanations and solutions and it’s hard to know what is correct when they try to keep everyone in the dark.

Service advisors are salespeople first and often don’t know shit about what they’re saying and it’s a game of telephone between them and the technicians who usually have zero respect for the service advisors and have little motivation to explain to them what’s going on.

Also, who knows if the splines and wheel speed sensor were damaged by the parts failure, or by trying to extract the stuck bolt.

No argument, it's a safety issue so I think this warrants a full recall not just a TSB... but when I was a comeback for the same squeal returning, they note there's no TSBs out for this issue. They couldn't duplicate the issue and it seems like it maybe was a case of something getting caught in the dust shield or something... I don't know but the squeaks gone away.

 

[Buyer2021]

The hub assembly is still held on by the brake disc and brake caliper. From what I understand, the only harm is accelerated wear to the press fit splines and the hub seals and bearings.

Actually 'The Bolt' plays no role in retaining the hub assembly on the axle housing, the hub assembly is fastened to the axle housing with four bolts through a flange. Note that on this specific axle the inboard end of the axle-shaft simply slips into splines at the differential with no circlip or similar retaining it on the inboard end. When you remove the caliper and the four bolts holding the wheel hub to the axle housing the entire axle-shaft with hub assembly intact can be removed from the axle housing.

IF you experience brake-rotor rubbing after the bolt has broken that indicates the internals of the hub are damaged and allowing displacement of the rotating part of the hub assembly relative to the non-rotating part which is fastened to the axle housing. 'The Bolt' may play a role in pre-loading and/or locating the bearings within the hub assembly.

 

[hotrodmex]

Actually 'The Bolt' plays no role in retaining the hub assembly on the axle housing, the hub assembly is fastened to the axle housing with four bolts through a flange. Note that on this specific axle the inboard end of the axle-shaft simply slips into splines at the differential with no circlip or similar retaining it on the inboard end. When you remove the caliper and the four bolts holding the wheel hub to the axle housing the entire axle-shaft with hub assembly intact can be removed from the axle housing.

So, I still haven't seen if one of these hubs has come apart, but this assumes that there is a tapered roller bearing in there, and not a single row ball bearing.

To me this is shaping up to be like a FWD axle setup. I think it is likely a single row bearing, which means the axle/bolt does have a function in keeping the hub together. Without some kind of retention, a single row bearing can wear super fast if the axial load goes over the maximum rating, or if you are applying a constant torque to it (wheel not parallel to the axle tube). If it happens to be a double row it can even come apart.

If the bolt and axle weren't there, I don't believe the hub could support the truck on its own very long.

Which also means they should have made the axle have a threaded end, like a front drive axle, maybe?

 

[Pedaldude]

Actually 'The Bolt' plays no role in retaining the hub assembly on the axle housing, the hub assembly is fastened to the axle housing with four bolts through a flange. Note that on this specific axle the inboard end of the axle-shaft simply slips into splines at the differential with no circlip or similar retaining it on the inboard end. When you remove the caliper and the four bolts holding the wheel hub to the axle housing the entire axle-shaft with hub assembly intact can be removed from the axle housing.

IF you experience brake-rotor rubbing after the bolt has broken that indicates the internals of the hub are damaged and allowing displacement of the rotating part of the hub assembly relative to the non-rotating part which is fastened to the axle housing. 'The Bolt' may play a role in pre-loading and/or locating the bearings within the hub assembly.

https://www.f150gen14.com/forum/thr...this-is-part-failure-on-axle.8963/post-212063


Starting at the above post, details emerge on what the axle bolt does.

Only the static half of the bearing is held on by the four large visible bolts on the HD axle. The half that rotates with the wheel, so far seems to only be held on by the brake caliper, bearing races/seals and axle bolt.

Until a bearing is sectioned and taken apart, it’s hard to tell. It’s possible that the hub bearings aren’t serviceable and that there’s an extra flange that captures the rotating side of the hub even if the bearings were trashed. I’ve seen some bolt-on rear axle bearings from FWD cars seemingly completely wallered out and still stay together, even after being taken out of the assembly.

Searching my VIN, I was able to find the axle retainer clip in the differential section. Though again; until someone takes one of these apart, who knows?

I think that I was just reading your compilation of axle bolt failures on the other Ford truck forum!

So, I still haven't seen if one of these hubs has come apart, but this assumes that there is a tapered roller bearing in there, and not a single row ball bearing.


Which also means they should have made the axle have a threaded end, like a front drive axle, maybe?

A threaded axle certainly would allow for a larger fastener, look at the socket size for FWD subcompact axle nuts and it definitely doesn’t make sense to Joe Average when looking at 9.75HD axle bolt.

There’s been talk of finding one of these at a junkyard and seeing what is actually going on with it.

 

[Buyer2021]

https://www.f150gen14.com/forum/thr...this-is-part-failure-on-axle.8963/post-212063

Starting at the above post, details emerge on what the axle bolt does.

As you point out in this post, the section diagram is not of the axle in question and the internal of the hub assembly could very well be something totally different in any number of significant details. Think what you will but personally I agree that until someone actually sections the hub assembly on our vehicle we really have no idea what's going on in there, the configuration of the bearing(s), the role of 'The Bolt'.

Searching my VIN, I was able to find the axle retainer clip in the differential section. Though again; until someone takes one of these apart, who knows?

While the Motorcraft Workshop Manual (WSM) for the 2021-2022 F150 lacks detail of the hub assembly internals (that because it is a non-serviceable assembly), it does have extensive detail regarding R&R of the 3/4-float 9.75" axle (distinct from the 'standard' (non-3/4 float) axle which is covered in different subsections of the WSM.

Reference to the applicable sections of the WSM makes it explicitly clear that the 3/4-float does NOT have a groove & circlip on the inboard (differential) end of the axle shaft. The step-by-step WSM procedure with diagrams for R&R of the 3/4-float axle shaft calls for removal of the four bolts holding the hub assembly to the axle housing, then simply sliding the axle shaft which is pressed into the hub assembly out of the axle housing as one complete unit. Unlike all other 2021-2022 F150 axles, R&R of the 3/4-float axle shaft does not call for removal of the differential cover to access and remove a circlip at that end.

Similarly, WSM sections specific to servicing the differential with 3/4-float axle uniquely show there is no inboard axle-shaft retainer of any sort on the 3/4-float axle.

I suggest that the WSM is an authoritative and definitive resource in this respect.

 

[bowling]

So, I went to McLarty Daniel Ford in Fayetteville, AR today, and mentioned the 550+ posts on this thread (and the thread on the other forum http://bit.ly/3Tkluqa ) with similar sounding PowerBoosts with Max Tow package just like mine and asked them to check things out since mine is making similar noises. They heard the noise (like metal and rubber - check out my video https://youtu.be/9bMME5G18dk) right in the service drive and after inspecting the truck, checking "everything," and even driving it three miles and hearing the noise, they then said everything is fine and safe and sent me on way. I have to wonder if they even took off the wheels to look at the axle bolts, as the receipt also indicated they had given my truck a courtesy wash, which would have been nice, but it was just as dirty as when I dropped it off.

Needless to say, I'm going to be taking it to another dealer shortly. Nice people, but I have no confidence in their diagnosis.

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