Pitman Arm Question

[saxman657]

Just recently rebuilt my 7 tooth steering system for my 28 Model A. Installed a new sector shaft and worm as a part of the rebuild. My pitman arm fit fine on my old sector shaft, but upon installation I'm finding it doesn't want to fit on the new sector shaft. I tried opening with a large screwdriver and wedge, but no luck.

Any suggestions? Do I need to file down the the internal portion of the pitman arm to fit?