56 f100. Took off my wiper arms and was surprised that they are not the same. Maybe not that surprised since this truck is a compilation of all kinds of parts. The driver side "nub" is pretty straight forward, a round grooved ring that is press fit on a smooth post. It accepts the wiper arm that has grooves on the inside. The passenger side "nub" is just the smooth post. It looks like the press fit ring is missing. That would be an easy enough fix except that the two arms are different. The driver side arm is cast with the grooves in it. The passenger side has a piece pressed into it that fits over the smooth post. If you could get the piece out there would be no grooves inside. Can anyone show or tell me how they are supposed to be? I will try to post pics.................OK so no luck posting pics. Sorry for long post.

 

It sounds to me like in your prybar removal technique, you broke your wiper pivots, and pulled the 'grooved piece' off with the wiper arm. You may want to look into getting the proper tool for the next time, as described in the thread I linked you to previously.

 

I can see why you would come to the conclusion that I broke it if you were in on my previous thread and didn't see it in person. I think I got the pics to load. The smooth post looks to have been cut or filed previously. The housing on the good(driver) arm has grooves cast into it while the passenger arm is much thinner where it slips over the pivot. I feel that if I took the grooved part off of the driver side pivot and put it on the passenger side, the passenger side arm is not the same design and wouldn't fit. Might have two different pivots and two different arms, YOU CAN'T RULE THAT OUT. Really need to know what it is supposed to be like. Both wipers were functional.Thanks

 

You broke off the knurled piece on the one, it's still inside the wiper arm.

Should look similar to this below

 

Thanks for the reference picture. I was confused because of the difference between the two arms. Wasn't sure if it was done for a reason. Looks like I can find original style replacement parts.When I get back in town I will get the piece out of the wiper blade and then see where that leads me. Probably to an f100 catalog. I will go ahead and order a wiper removal tool. Thanks ALBUQ F-1