Wiper motors

I do a lot of touring with a variety of old cars including ones which never had wipers. On pre-1950’s cars the swept area of working wipers is so small that even if the wipers work, I RELY ON RAIN-X. Don’t drive an old car without it! Their anti-fog interior product however, I can’t recommend.

Repair of vacuum wipers can often be as simple as a squirt of light oil. If the housing is warped so that vacuum is leaking, I’d probably try careful filing to square the surfaces, much like milling heads surfaces. The membrane can be replaced with thin leather or with a modern plastic flexible film.