The Ford Barn

mcgarrett · 08-31-2025, 09:47 PM

I picked up a couple of 1940 Ford wiper motors recently that seem to be in really nice shape. The motor action on both of them is very smooth and the suction feels really strong. After I confirm they are in good working order I plan to install one of them - the one in the car is DOA.

I've read a few posts here on the Barn that advise to introduce some Marvel Mystery Oil into the vacuum port and work it into the flapper valve mechanism. Is that still the preferred maintenance method or is there something better to go with? Replacing the wiper motor on a '40 Ford is a real pain, so I want to make sure to do it right the first time!

08-31-2025, 09:47 PM	#1
mcgarrett Senior Member Join Date: Dec 2013 Location: Corsicana, Texas Posts: 1,551	'40 Ford vacuum wiper motor maintenance I picked up a couple of 1940 Ford wiper motors recently that seem to be in really nice shape. The motor action on both of them is very smooth and the suction feels really strong. After I confirm they are in good working order I plan to install one of them - the one in the car is DOA. I've read a few posts here on the Barn that advise to introduce some Marvel Mystery Oil into the vacuum port and work it into the flapper valve mechanism. Is that still the preferred maintenance method or is there something better to go with? Replacing the wiper motor on a '40 Ford is a real pain, so I want to make sure to do it right the first time!