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Just reinforcing Don's comment, the taper surfaces must be CLEAN and DRY, very important!!

Torque the nut to spec and recheck it again after a hundred or so miles.

Appreciate the help. I didn't find a totq spec in manual I assume torque per nut/thread size?

Its in the manual, page 10 of the Rear Axle section, 200-270 ft-lbs.

Not sure how I missed it. Thanks much!

Just curious, Dave - is 200 - 270 ft lbs not quite a range?? That's over a 30% 'from/to' for the spec; seems like a lot?? Chris.

The range is perhaps the result of there being 1/6 of a rotation between cotter pin positions.

Got it... makes sense, thanks for clarifying. Chris.

Is the main cause of broken rear axles not having the nut torqued correctly?

JW, One of the failure modes, that is a 'one per rev' fatigue failure at the fillet radius between the taper and thread, is believed to be a result of taper/hub relative motion. Insufficient torque may start that whole process. I know for a fact that after I replaced my '48 broken axle I went back 100-200 miles later and found the torque was well below the minimum required. Trust me, I know it was 'in spec' at 0 miles.

I sent my broken parts to some materials engineers that reported back the mode of failure. I also have some good close-up photos showing the multiple origin planes.

In addition, tribal wisdom for the folks that care for other antique cars that have the same tapered design swear by the 're-check the torque' process.

If you see a 45 degree fracture inboard of the bearing that would not be a result of low nut torque.

dp

Good to know, will recheck the torque after I get some mileage on the car.
Thanks!