Mike - There is no flange there as that piece goes over the exterior diameter of the axle tube. You really need to have a bearing puller like what is pictured in the shop manual diagram. The inside bearing retainer (large flat like washer behind the bearing), bearing and seal when installed per the manual are driven in with a setting tool and hammer blows. Slight press fit, so a puller is necessary to overcome that interference fit to remove from the bearing bore. The process for removal/installation is the same for your '40 as is shown in this page from a
Chevrolet '38 Shop Manual.
This
fairly recent thread may provide some helpful leads on tools and the process others have taken to get the bearing out. Let us know how it turns out.
