The existing brakes were in a very sad state and in need of refurbishment.
Found it easier and more cost-effective to replace the entire assemblies than to reline the old brake shoes & machine the drums
Another deciding factor was that the brake drums are no longer manufactured, meaning once they reached maximum machining I had an issue. Also finding wheel bearings to fit them was difficult ... had to be imported from an obsolete parts dealer ... not a good situation for ongoing long-term maintenance
I wanted to fit heavy-duty bearings rather than the standard ones that come with the later model drums.
A primary issue was that there was no inner bearing which matched up any late model 12" drums to the Silver Streak stub axle.
I located heavy duty bearings that fitted the stub axles and had the inner bearing collars on the new brake drums machined out 5mm ... problem solved!
Then found that I needed to take 15mm off the grease cap collar (otherwise getting the split pin into the locking nut was virtually impossible) The original SS axles are shorter / stumpier than modern brake drums are designed for.
May seem a bit 'over the top' to re-engineer modern brake drums to fit the SS stub axles, but my reasoning is that I'd be replacing wheel bearings a lot more often than brake drums .... and let's face it , the old drums were functional for over 40 years!