Technical READ NOTE PLease! Broken axle shaft Right side and tonight the Left side broke.

looking at the pictures there appears to be rust in the cracks. looks like old damage. There should not be rust in the crack if it is in the bearing area as the lube should prevent that. I would look for a new housing or do a full teardown to see what you have.

 

Both of the axles you show in the pictures have been cracked for quite some time. The beachmarks on the one are a dead giveaway for that one. See where it looks like waves have washed up on the beach and left curved lines? Those are where the metal, cracked, then stopped, repeatedly. When there wasn't enough strength to resist the next load, the shaft failed with the granular looking area being how much of the shaft wasn't cracked through.

No doubt those had been cracked a while, many cycles if you will.

 

Rear end looks like it was rode hard and (literally) put up wet. Junk.

 

i'm with the guys that say that Nova was badly abused or was in a serious accident and/or major rollover. that rear end had issues long before you broke the axles.

 

If there's rust on an axle, it's not a very good indicator that everything is just peachy smooth and hunky dori. Quite to opposite. The rust in the break tells you that it was fractured long before it severed into two pieces on you.

How long does it take an axle to rust while its soaking in gear lube?
The answer is it will stay rust free indefinitely.

 

How long does it take an axle to rust while its soaking in gear lube?
The answer is it will stay rust free indefinitely.[/QUOTE]

There isn't much gear lube at the end of the axle. I am usually surprised at how dry the GM rears run at the ends. When you pull them your hands get hardly any oil on them at the bearing end. That rear may have sat for a few years before being put to use.

 

Call Dutchman Motorsports, feal good people to deal with. They can help you with axles and C clips. Those axles have had a set of slicks bolted to them I'd say.

 

Yes, Kevin is quite correct, this is a classical fatigue failure. From the pictures it looks like multiple cracks have formed under rotating bending loading and grown until they merged. The resulting cracks extended microscopically every revolution of the road wheel until the combination of the stress and the crack size overwhelmed the toughness of the steel, and the final failure occurred.
The interesting thing - to me anyway as this was my job for 30 odd years - is that the initial cracks look like they started on the same plane. It looks like they were at the edge of the wheel bearing and there may be some damage at this point or machining marks to help things along. Whatever the cause it started a long time ago and I very much doubt it was anything to do your driving or maintenance.

 

Sorry I could not label those pictures.
The axle shaft in the vise is the Right side that was the first to break.
It has been sitting out on a table in the weather until today when I brought it in and cleaned it up and took the pictures.

 

When I installed the Right axle shaft which was the first to break it went in very easy.
This one I am not sure what to do as far as replacing the Left axle shaft or both axle shafts.
Or buying a completely new rear axle??

 

Sorry, that axle was the first to break and it was out in the weather on a table. I took it in to take the pictures today.

 

Sorry, that axle was the first to break and it was out in the weather on a table. I took it in to take the pictures today.

 

Sorry, that axle was the first to break and it was out in the weather on a table. I took it in to take the pictures today.

 

Sorry, that axle was the first to break and it was out in the weather on a table. I took it in to take the pictures today.

 

Bingo!

 

Yes I got it earlier.

 

Really amazing how long things last under those conditions isn't it. Super hard surface with a bearing running directly on it and much of the loads are cantilevered out right past that bearing. Hard to believe they last at all, truly a testament to large fudge factors. Certainly wouldn't need a over 1" thick axle to handle just the torsional loads from it's initial application. Fatigue failures are most interesting.

 

I'd pull the right one out for an inspection, but it's probably fine. If the diff is ok, I'd put it back together with a new left axle and be done with it.

 

I would never feel safe with that rear end, replace with a known good unit for piece of mind.

 

Sorry, that axle was the first to break and it was out in the weather on a table. I took it in to take the pictures today.

 

Can anyone recommend a place to inspect the broken axle shafts to truly determine their history?

 

Can anyone recommend a place to inspect the broken axle shafts to truly determine their history?

 

You could have a machine shop compare hardness of the axle at a good section and work towards the broken area and right at the break itself.

 

OK, thanks I am going to make some local calls tomorrow.

 

If you have an airport of some size nearby, check with a repair service and find out if there is an NDI shop available. NDI stands for non-destructive inspection. They spend their lives inspecting and finding causes in aircraft parts. They should be able to do a good post mortem and tell you the cause. Either that or find a USAC certified machine shop that can mag or zyglo or other NDI services. Any local racer should be able to steer you in the right direction. When we ran a sprint car, we had to have fresh mag papers on steering components at the beginning of the season or after a crash. I agree that those cracks with rust indicates that they started propagation some time ago.

 

Why bother? you already know the broken ones are crap! If the center looks and rolls nice make sure it's clean. Buy a single or new pair of axles, Moser, Currie, Johns, Dutchman (even stock ones) and new wheel bearings and seals. Make sure center pin is in spec, (correct end play on axles when installed) new c-clips. Put it all back together and you will be back on the road, I'll bet it will last a long time. There are still millions of them on the road. Then you can wonder how long till that parking paul in the trany brakes.

 

Not nearly junk! How can you tell what the rear end looks like?
I surely think it has been abused by someone at some time but this was built many years ago and driven for many miles.
But yes someone certainly abused it.
One great point was made that the rear axle may have been that way when it was put into the car many years ago.

 

Gosh, I wonder if some of these guys even read,
( rust? what about the rust) ( what caused the rust)

O, yeah what color you goin' paint it.

 

Got it back on the road yet???