Yet another failed axle bolt

[simon]

I had my truck in for scheduled maintenance at the dealership today when they came back and told me the axle bolt is failed and I have to keep the truck there for 5 days for the part to get in. The truck is "unsafe" to drive and they have no loaners and no avenue to help. I asked if they expected me to walk home, and after some discussion back and forth gave me the keys to my truck with the broken fastener in the cup holder. I can't NOT have a car to drive and would really prefer not to have buy a rental for however many dollars per day it'll cost.

Since I don't have the best understanding of the 3/4th float axle, can someone help me understand is this really a safety issue or is Ford just being extremely conservative? What is the purpose of this fastener?

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[HammaMan]

When the bolt fails the axle can slide into the diff and strip the remaining splines leaving the rear end unable to provide propulsion. If you're pulling out in traffic and lose all power a collision is a probability.

 

[Paul Neubauer]

My dealership gave my truck back to me to drive with both sides broken and said there was no safety issue until the backordered axles arrived.

 

[FaaWrenchBndr]

When the bolt fails the axle can slide into the diff and strip the remaining splines leaving the rear end unable to provide propulsion. If you're pulling out in traffic and lose all power a collision is a probability.

The way the differential is made and the spider gears, I find it hard to believe that the actual shaft can move inward more than a quarter of an inch per side.

I’m not sure where you got that information but I’m gonna need some convincing on that one cause I don’t buy it.

 

[Paul Neubauer]

The way the differential is made and the spider gears, I find it hard to believe that the actual shaft can move inward more than a quarter of an inch per side.

I’m not sure where you got that information but I’m gonna need some convincing on that one cause I don’t buy it.

 

[simon]

The service advisor did say Ford does not approve rentals for this repair and the truck has to be at the dealer for them to order the part. This is, unfortunately, consistent with the document. Annoying of Ford

 

[FaaWrenchBndr]

Oh, I’ve seen a recall.

That doesn’t tell me jack shit. I’ve had many differentials out. I’ve had many axle shafts out. I just don’t buy it. There’s not enough room for the axle shaft to migrate inward an inch & a half to eat the spines off. It just ain’t gonna happen

 

[HammaMan]

Oh, I’ve seen a recall.

That doesn’t tell me jack shit. I’ve had many differentials out. I’ve had many axle shafts out. I just don’t buy it. There’s not enough room for the axle shaft to migrate inward an inch & a half to eat the spines off. It just ain’t gonna happen

We've had it happen to at least 3 members here. They had to go into 4WD to get off of the highway.

There's at least 1 discrete thread on it, others are buried in the numerous threads on the topic. This issue is ~18mo old and still no resolution.

 

[v8440]

We've had it happen to at least 3 members here. They had to go into 4WD to get off of the highway.

There's at least 1 discrete thread on it, others are buried in the numerous threads on the topic. This issue is ~18mo old and still no resolution.

That old classic, a collision between theory and reality...

 

[FaaWrenchBndr]

We've had it happen to at least 3 members here. They had to go into 4WD to get off of the highway.

There's at least 1 discrete thread on it, others are buried in the numerous threads on the topic. This issue is ~18mo old and still no resolution.

OK, thanks for the insight.

I’ll do some digging and I’ll educate myself. It’s a shit design. I would’ve liked to have had the extra towing capacity provided however, I certainly did not want this axle in my new truck.

 

[HammaMan]

OK, thanks for the insight.

I’ll do some digging and I’ll educate myself. It’s a shit design. I would’ve liked to have had the extra towing capacity provided however, I certainly did not want this axle in my new truck.

Here's one
https://www.f150gen14.com/forum/thr...loded-ford-tech-said-3rd-one-this-week.19644/

 

[HammaMan]

and another
https://www.f150gen14.com/forum/threads/2022-f-150-powerboost-rear-end-failure.19933/

 

[FaaWrenchBndr]

Ok….. thanks for the schooling.

well, I have read that this can and is able to happen. I still can’t wrap my head around how the axle could migrate inward far enough to disengage the splines at the hub. This asinine design is even more mind-boggling.

I appreciate the corrections folks

 

[oncechance]

Ok….. thanks for the schooling.

well, I have read that this can and is able to happen. I still can’t wrap my head around how the axle could migrate inward far enough to disengage the splines at the hub. This asinine design is even more mind-boggling.

I appreciate the corrections folks

Respect. Taking it as it should be taken and not getting mad or defensive. Being accountable.

 

[astro_fusion]

Ok….. thanks for the schooling.

well, I have read that this can and is able to happen. I still can’t wrap my head around how the axle could migrate inward far enough to disengage the splines at the hub. This asinine design is even more mind-boggling.

I appreciate the corrections folks

You're not the only one, I've built and had many rear ends apart also, this collateral damage doesn't make sense. Spider Gears have a center pin that at least in my experience keeps the shafts from working too far inboard off the diff splines. Maybe Ford did away with that redundancy and saved a bit of material off that pin and our assumptions are wrong?

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