Rear axle broke again (1 Viewer)

[jmh8660]

Has any one ever seen a break like this before? Pretty sure it’s poorly performance casting issues. Going to clean out and replace with nitro and new bearings until I fix properly… Any ideas on how or why it broke would be appreciated.

 

[klinetime574]

Doesn’t seem odd to me for a 35+ year old part to break. What’s up with the splines at the end?

What were you doing when it broke? What size tires are you running? What gear ratio in the differential(s)? Locker? How much weight do you carry in the rig? Just thinking of data we could add to this equation.

 

[jmh8660]

Doesn’t seem odd to me for a 35+ year old part to break. What’s up with the splines at the end?

What were you doing when it broke? What size tires are you running? What gear ratio in the differential(s)? Locker? How much weight do you carry in the rig? Just thinking of data we could add to this equation.

coming to a stop street driving. Less than 5mph at failure
295/70r17
4.1 lockers yes (not locked when broke)
Heavy. Bumpers,tank, sbc ,700r4
I replaced both axles 7 yrs ago with poly performance after break on rubicon. Less than 20k on them. Left side wore down in bearning housing (not seized) 3yrs ago and was replaced with oem.
Spline at the end most likely damage due to failure?.?. I think I may need to get into 80 series rear axle. 3rd issue I’ve had with these 2nd time if lost a wheel. Bad batch of axles, bad housing/bearings, bad luck?

 

[lcwizard]

I don't like chromoly for a semi float axle. It works well as a full float but the bearing surface, when used as a semi float work hardens and wears or breaks.
My first experience with moly axles in a cruiser semi float rear was 35 years ago . I had Summers Brothers build chromoly axles. After about four years and 40K miles,
the first one broke at the bearing surface. The second broke at the same place within a month of the first. I talked to Moser and Strange. Both concurred
that Chromoly shouldn't be used as the bearing surface. It's good for twisting loads but doesn't wear well as a bearing steels like 52100 which has twice the chromium content

 

[OSS]

what a nightmare

 

[jmh8660]

I don't like chromoly for a semi float axle. It works well as a full float but the bearing surface, when used as a semi float work hardens and wears or breaks.
My first experience with moly axles in a cruiser semi float rear was 35 years ago . I had Summers Brothers build chromoly axles. After about four years and 40K miles,
the first one broke at the bearing surface. The second broke at the same place within a month of the first. I talked to Moser and Strange. Both concurred
that Chromoly shouldn't be used as the bearing surface. It's good for twisting loads but doesn't wear well as a bearing steels like 52100 which has twice the chromium content

That’s really good to know. Thank you very much for your insight. I’m really leaning to the 80 rear axle swap at this point. Keep the leafs? Or do you think it worth the effort for coils? I’m planning on picking up an 80 frame with axles.
My bumpers are awesome absolutely rock solid.
Thanks again.

 

[lcwizard]

That’s really good to know. Thank you very much for your insight. I’m really leaning to the 80 rear axle swap at this point. Keep the leafs? Or do you think it worth the effort for coils? I’m planning on picking up an 80 frame with axles.
My bumpers are awesome absolutely rock solid.
Thanks again.

Doing leaves is certainly less complicated and probably cheaper. I like leaves, but I build them to my spec so they ride very well. I friend with a Emu'ed 80
drove mine 60 on one trip and said he could really see a difference in ride quality. I can comfortably do a road that you take at 25mph with off the shelf springs,
at 40~45 mph. Either way, coil or leaf, you add airbags if you go between heavily loaded trips then back to empty

 

[cruisermatt]

Poly Performance. there's your issue