Could replacing the broken pinion coupling rivet and torque tube bushing solve the problem?
No, if your talking about the perpendicular problem.
Yes,to stop the propeller shaft from being worn down.
I'm pretty sure the reason why the pinion-to-propeller
shaft coupling rivet was broken in half is because the
propeller shaft was floppy around because of the rear bushing was trashed.
This happens because the oil seal was leaking tranny gear lube
or the tranny was low on gear lube.
You can still use the propeller shaft because the Okie bushing
rear bushing will ride on a spot just ahead of the wore spot.
Okie bushing Sleeve Assembly cross-section view The effects of some accident or misalignment that has trashed everything else?
Misaligned torque tube would not trashed everything.
The perpendicular problem is a different deal.
I guess it depends on how far it is misaligned.
Maybe at one time someone smacked into a curb
with the rear wheel while making a turn
and that shifted the axle over.
Sometimes its so misaligned that you can't bolt it up to the tranny.
If you can't straighten it out then its time to scrap it.
What needs measuring to see if the 3.90 setup is worth fixing?
Bring it to a machine shop to find that out.
Does anybody know specs for the coupling rivet to source locally? Are there oversized ones
5/16" diameter
I'm sure there are different sizes.
The way you described the axle and torque tube.
Sounds to me like its just plane wore out and it has been damaged.
If you can't get the torque tube 90 degrees from the axle plus or minus a couple of degrees.
If that is the case its time to throw in the towel.
The propeller shaft torque tube housing is riveted into the cast carrier housing and if those rivets are loose or
the rivet holes are elongated it would be not cost effective to repair.
1954 Torque tube 1954 Cherolet Specification packet