[MENTION=544031]Pantah[/MENTION]

That stem was not in far enough, the whole expander must be below the threads.

Aluminum fork, steel steerer, vibratory mismatch in the long run?

Did you start riding this more, harder than PO?

Also, a wire wheel on a bench grinder makes very short work of rust, paint and PC, 50 or 100 grit sandpaper to start then let er rip.