New Here...quick question and intro.

[BHB]

Hi all....Just posted up a quick intro in the welcome area:

http://67-72chevytrucks.com/vboard/s...d.php?t=515089

Now for my question:
I just pulled the heater box to replace the heater core and found that it needed some TLC (specifically the vent doors are corroded and the foam is all flaking off). I've got the box disassembled except I can't get the pins out to release the vent doors from the plastic unit. These are the pins that have the arms on them that the cabling hooks to in order to open and close the vents. Any tricks to getting these pins out? I started trying to knock them out with a hammer and am making minimal progress. Any tips greatly appreciated. Thanks!