I don't know what model you have, but on a 46 Chevy the bracket that holds the door open is entirely different. It has a rubber end and you have to insert it through the kick panel area.
There is a plate with two loops that the bracket has a pin that secures it to both areas. I wish I was more articulte in describing what I am talking about! Look in the Jim Carter site or catalog for a 46 or later truck and you will see what we are talking about! I think they call it a door check!
