Classic car windshield wiper vacuum motor replacement

Picture of Classic car windshield wiper vacuum motor replacement

Up until the 1960s, most automobile windshield wipers were powered by vacuum motors.  I have a 51 Willys pickup with a vac motor.  The last time I registered the truck, the only way I could get the wipers to pass the inspection was to mist the windshield with a water spray bottle before turning them on.  It is time to reregister the truck and the wiper motor has failed. 

This Instructable describes the process I used to convert the wipers from the original vacuum motor to a 12 volt motor.  If you choose to make this conversion,  I suggest you read through all of the steps before starting.  These instructions are a little disjointed.

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Step 2: Determine the motor drive radius 1st step

Picture of Determine the motor drive radius 1st step
To determine the radius of the motor drive, I made a cardboard template, attached it to the drive side of the motor, and marked the outer arc swing limits of the upper hub wing.  The initial photo showed only the index markings, but is was a poor photo.  I made this photo after I had taken the template off, penciled in the radius line extensions, and remounted the template to the motor.

Step 3: Deterimining the radius 2nd step

Picture of Deterimining the radius  2nd step

Using a protractor,  the radius of the vac motor drive arc is shown to be about 140 degrees. 

You did a fantastic job! I'll second the photo request, I love classic trucks! By the way, did she pass inspection?
pmartinez3 years ago
Please post a pic of your car, would love to see it.
Culturespy3 years ago
Good to know for anyone with a classic car!

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