Trail fixing snapped front axles:

[ThunderFlash]

I've never had the pleasure of a broken axle, but is that a typical failure from what you guys have seen? It looks to be super brittle.

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[Valhalla]

No, usually CV.

 

[ThunderFlash]

No, usually CV.

I was curious more specifically about an axle failure. What looks to me to be a very brittle failure is indicative of extremely hard/low ductility material, which snaps like a uber high strength/"low" toughness tool steel drill or reamer would fail with lots of little fragments.

I would have thought an axle would not be through hardened to be harder than hades all the way through the core, but tougher/more ductile in the core and maybe a case hardened or carburized outer surface for a combo of good wear characteristics, strength, and toughness.

Maybe shattering is typical of an axle failure, I really don't know, but maybe you got bad material or a poorly processed axle. Bad chemistry, microstructure, or thermal processing can do things like that. I wouldn't think an axle should shatter, even under extreme duty usage.

Now I have the Stones Shattered stuck in my head. Crime rates going up, up, up, up, up! To be living in this town you must be tough, tough, tough, tough, tough, tough!

 

[zuke]

I was curious more specifically about an axle failure. What looks to me to be a very brittle failure is indicative of extremely hard/low ductility material, which snaps like a uber high strength/"low" toughness tool steel drill or reamer would fail with lots of little fragments.

To be fair, what was actually shattered was the spline shaft on a tripod joint, Which is a machined part that probably is hardened deeper into the material than a straight axle shaft.

It DID give some first, which is why he was left with a big enough piece of spline to require him extricating it from the housing.

We haven't seen enough of these failures yet to say if that is going to be typical for them or not, but it wouldn't surprise me if this is a kind of failure we see going forward.

 

[ThunderFlash]

it wouldn't surprise me if this is a kind of failure we see going forward.

There is a trail in Tahuya ORV park named "Broken Axle" that I have to date avoided for this reason!

 

[Valhalla]

I broke a lot of 9" and Dana 44 axles down through the years. This looks typical for an overloaded 29 spline in my opinion. I can see where it wanted to twist as the stress was put on it. Don't forget I drove out on this. Pieces were hitting as the front end differentiated

32 spline will be better for the weight and size tire I run. I really wanted RCVs but the reports on here are mostly negative.

 

[ThunderFlash]

I'll be hornswoggled....looks like they sometimes use 4340 (maybe 4340M) and 300M steel on the axles. Don't know what heat treat they use, but that stuff is typically thru hardened and can get up in the 300 ksi tensile strength realm which would get on the brittle side of things and not so great with notch sensitivity. Those alloys are often used in aircraft landing gear and other highly stressed parts. I'm impressed.

 

[zuke]

I broke a lot of 9" and Dana 44 axles down through the years. This looks typical for an overloaded 29 spline in my opinion. I can see where it wanted to twist as the stress was put on it. Don't forget I drove out on this. Pieces were hitting as the front end differentiated

32 spline will be better for the weight and size tire I run. I really wanted RCVs but the reports on here are mostly negative.

I'm curious, did you get the spline out yet, And was it twisted, Or did it have a clean break?

 

[Snacktime]

The inner CV splines being the fail point isn't that common. Most of the time it's the race or the bell cracking. Then you break the intermediate shaft or the coupling which will take out the FDU passenger tube.

Literally a roll of the dice and to much to carry to do a trail repair.

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