Any help? Stem seems to be stuck - Seized quill stems

If you don't mind sacrificing the stem, then you could cut the top section off with a hacksaw, leaving a column inside the steerer, with the remains of the expander bolt. Tap the remains of the bolt downwards to free the expander wedge, then get a stillson on the remains of the stem to twist it free.

I'd try drilling out the bolt first though, as you may be able to save the stem and only need a new expander bolt.

Ok, thanks. Guess I'll be giving this a go then.