Are we talking the same part? To me, and most others, the wiper arm is the shiny arm that the rubber blade attaches to. It sounds like your talking the shaft that connects the actuating arms through the body to the wiper arms. If so, someone else will have to chime in as I have never removed the shafts before.🛠

Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
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USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)