Heater box question non AC truck

[Chaz]

Replacing my heater core and blower motor. When I took out the blower motor I saw there is a partially open vent door just behind the blower motor. It's not operated by a cable.....looks like it was vacum operated.....how can I remove the vent door? I want to have good airflow from my new blower.

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[Chaz]

Pic of the vacum diaphragm with hose broke off

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[Chaz]

I never had any good airflow when the blower motor was still working.......maybe it was due to the vent door partially open......if I am somehow able to rip it outta there is it gonna cause problems? I don't want heat blowing out through the kick panel vents.....I just want good floor heat and defroster......

 

[Chaz]

1989 suburban V2500