What do you use to lubricate the vacuum windshield wiper motor? I assume that insides are made of leather and that it would apply from 1931 to 1954 vacuum wipers. What procedure would I follow to ensure that it continues to operate efficiently for a number of years?

For what it's worth, I used WD-40 on my 1930 Coupe Windshield Wiper motor. It was operating slowly, with the WD-40 it operates smoothly. But I think it depends on the condition of the motor, there's only so much lubrication can help.

Marvel Mystery Oil works too.
Sid