[DavidG]

Originally there was a 1/2" x 1/8" arm riveted to a pair of tabs on the A pillar and curved on the end that inserts into a slot in the front of the door. A unique rubber bumper (B-46590) is attached to that end inside the door with a thick slotted washer (B-46596) and cup with tabs (B-46594) to secure the slotted washer. There are three pairs of notches at the door end of the arm in which the slotted washer is inserted providing three different effective lengths of the arm depending on the body type.

In addition a 1/4" thick rubber pad (B-80498 for commercial vehicles) was attached with two special #10-32 x 5/8" screws with a wide round slotted head on the inside of the front edge of the door. In the center of that pad is a slot through which the arm passes. So, rubber meets rubber in the original set up making for a soft stop. Except for the arm, all of the parts are shown in the various hardware catalogs of the mid-1930s. I believe that Bob Drake offers both the arm and the rubber bumper for the end of the arm with a different and easier to use means of retaining the bumper on the arm than the original setup. I don't recall anyone offering the pad attached inside the door, but it is easily made from 1/4" sheet rubber.