seized convertible top pump

[plugger340]

My convertible pump is seized and I was wondering what was the best way of freeing it. I've popped off the end cap to expose the armature and I can't turn it or pull it out. I can't apply a lot of pressure by hand and I thought someone might have ideas how to free it.
Any suggestions??

 

[jaws]

If its locked up, I would just get a new one, their not to spendy.