I have a GM Corsa 1.0 MPFI (Brazillian version of the Opel Corsa B) and today I started replacing some parts, including the water pump. I had heard from other owners and mechanics that sometimes this water pump gets stuck because of rust and it's really hard to remove, requiring that you "hammer" it out. With me it wasn't different. The water pump doesn't move out when I pull it with my hand.
Below is an image of a the working area, not from my car but probably the same model. The water pump is right below the alternator:
Any tips on how to remove it? Maybe other cars have similar issues with rusted water pumps. Even if I should use brute force, how should I hit the pump and where? I even thought about making something similar to a pulley remover and try to pull it out from the small gear, but I don't think it would handle the force.