1940 Cadillac

I'm looking for some info. My brother just bought a 1940 Cadillac with a '53 Caddy engine in it. A**** other things, the control knob for the windshield wiper system is broken off. Is this car a vacuum operated wiper system? I haven't seen it yet, but he says the broken stem is in a little narrow strip of metal at the center of the windshield and he cannot tell how it is mounted. Any information out there? Thanks in advance for any help.

 

pretty good odds that it's a va***n .

 

Vacuum, mounts with a nut from the bottom under the dash.

 

Thanks for the info... we'll probably be researching a retrofit electric setup for this at some point.