Sounds like you've tried to dissemble as it would easily come apart if all clean and new... But that's giving you trouble and you asked for more ideas.

Next try removing hub and drum together,
Or possibly hub, drum, shoes, and backing plate all together.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-