I lived in Minnesota for 14 years and in northern Illinois for more. That is not a rust issue. The entire end of the shaft is shiny and rust-free. If it were rust, most of the end would be corroded, with a small shiny spot at the point it finally failed.
That shaft looks like the shafts on my 1949 Chevrolet before I learned that “popping the clutch” has consequences.
Only a small amount of rust would be needed to create a high stress situation in a critical part like this.
The shaft didn’t fail due to RUST!
If failed due to torsional STRESS!
Tester
What do you think, manufacturing or design flaw?
Those shafts definitely have a ground down spot on them to locate the damper assy.
Been there… done that… Not too uncommon, but it def gets your attention when they snap. Do not pass Go, Do not collect $200
My opinion, right or wrong, is that the shaft failed due to stress. This was likely caused by the length of the shaft. There’s going to be an inherent amount of flex in just about everything.
Much like a straight piece of coat hanger: bend it enough and it’s going to snap.
That’s exactly what happened.
Over the years of applying torsional force to the shaft, especially where it tapers down at the damper, the shaft acted like a torsion spring where it slightly twisted. After fifteen years of this action, the shaft finally snapped.
Tester
All true, but I bet the corrosion in the exact place it snapped was a contributing cause.
It’s sitting on my bench not yours.
So I can tell you emphatically, RUST HAD NOTHING TO DO WITH THE FAILURE!
Tester
I thought there was some rust under the damper. No rust/corrosion? There was plenty on the axle in that video.
I suspect that the harmonic weight became out of balance and initiated the break at the groove that located it.