Yet another failed axle bolt

[FaaWrenchBndr]

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[Snakebitten]

@Snakebitten I torqued them to 90 ft lbs which is pretty damn tight, and way tighter than the factory ones were in there. My intent was to prevent any movement and therefore wear on the splines. Time will tell if that was the right thing to do.....

I did 84ftlbs I think. But that's far less than what the torque procedure calls for.

HammaMan, I don't know if they are one-time use or not, but if you tighten them as much as the spec calls for? I wouldn't use them twice. 12mm is NOT that big of a bolt and it feels creepy to tighten them that hard.

Since I'm willing to check, and even replace the bolt every tire rotation, I feel very comfortable torquing less.

 

[Snakebitten]

That 90° feels queasy.
It's like changing spark plugs. I have a sense, a feeling, of about as far as I'm willing to go. If the spec is much beyond that point? I ain't going to use the spec.

Honestly, I never knew someday I'd have experience with the kind of bolt that is used on this axle. Buy a vehicle, drive a vehicle, trade a vehicle and never have a clue about the torque spec or bolt locating the splined axle. ???

 

[scott011422]

That 90° feels queasy.
It's like changing spark plugs. I have a sense, a feeling, of about as far as I'm willing to go. If the spec is much beyond that point? I ain't going to use the spec.

Honestly, I never knew someday I'd have experience with the kind of bolt that is used on this axle. Buy a vehicle, drive a vehicle, trade a vehicle and never have a clue about the torque spec or bolt locating the splined axle. ???

When you check and replace that bolt, You you ever loosen the bolt and lightly rap on it with a hammer to see if the shaft is becoming loose?

 

[Snakebitten]

When you check and replace that bolt, You you ever loosen the bolt and lightly rap on it with a hammer to see if the shaft is becoming loose?

It's only been enough miles (~10,000) since I swapped out bolts to check them twice. Both times I pulled the bolts there's zero evidence of the fretting required for the splines to lose their pressed fit. I did push on the axles to see, but I didn't hit them with force.

Note that when I did discover a sheared bolt, you could easily push that axle in/out, and the tube was full of red powdered fretting dust from the hub material wear. (I think the hub splines are a softer metal than the cold steal axle splines?)

 

[PatchManager]

February '23 Build Date, after the recall dates. No issues, but replaced the bolts for insurance with Class 12.9 (Grade 9) bolts @ 90ftlbs wet. Easy enough to do while I was rotating the tires.

@Snakebitten If you're still collecting data, mine came out at less than the 30 ftlbs I had the torque wrench set to for removal. They felt like it was just the thread glue holding them in.


https://www.mcmaster.com/90373A125/

Did you reuse the factory washer or use new washers?

 

[JoeRedFly]

Did you reuse the factory washer or use new washers?

I just reused the factory washers. They're good solid thick washers, I don't have any concern there.

 

[FaaWrenchBndr]

That 90° feels queasy.
It's like changing spark plugs. I have a sense, a feeling, of about as far as I'm willing to go. If the spec is much beyond that point? I ain't going to use the spec.

Honestly, I never knew someday I'd have experience with the kind of bolt that is used on this axle. Buy a vehicle, drive a vehicle, trade a vehicle and never have a clue about the torque spec or bolt locating the splined axle. ???

Completely understand.
There are some cylinder head bolts that are torqued the same way. Torque to a spec, then tighten x*.
It’s damn crazy for sure

 

[Snakebitten]

Completely understand.
There are some cylinder head bolts that are torqued the same way. Torque to a spec, then tighten x*.
It’s damn crazy for sure

If that factory bolt, that comes in it's own bag, even remotely looked like the quality of a head bolt?

I know that if I was a metallurgy expert, I could probably explain why that bolt isn't as brittle or poorly machined as it looks. But I can't un-see it.

Fetch a new one.
Then hold it in your hands with a plain old Ace Hardware or Tractor Supply bolt of the same rating.

 

[FaaWrenchBndr]

If that factory bolt, that comes in it's own bag, even remotely looked like the quality of a head bolt?

I know that if I was a metallurgy expert, I could probably explain why that bolt isn't as brittle or poorly machined as it looks. But I can't un-see it.

Fetch a new one.
Then hold it in your hands with a plain old Ace Hardware or Tractor Supply bolt of the same rating.

Yep…..the bolts don’t instill confidence.
I’ve been used to aircraft hardware for many years. I’ve replaced wing bolts. Each damn bolt was like 425 each. Drop one and it’s trash. High tolerance, extremely high quality

 

[scott011422]

One the other hand, Do you really want to replace the bolt with one that doesn't break? As it stands, The factory bolt breaks when the pressed in splines have become damaged. Replacing that bolt kind of eliminates that tell tail of a bad shaft.

Unless of course you do as SnakeBitten does and routinely replace and inspect the bolt and the shaft.

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