vacuum wipers

[Terry K]

I have a '41 Ford with Vacuum wipers that do not work. I have used a Vacuum pump on the lines with no results--No vacuum. How do I test to fix the problem. Wiper switch or wiper unit its' self ?

[Doublepumper]

In my limited experience, it is either cracked vacuum hoses or gummed up wiper motor internals that cause most of the problems. Sometimes the motors and valve mechanism can be cleaned out of old gunk and lubed to get them to work again. Sometimes it's the paddle seal dried out and leaking inside the motor, which is harder to deal with. I haven't tried it but, supposedly brake fluid can be used to soften the paddle seal and get them to seal again.

Good luck!

[tubman]

The wipers on my '51 weren't completely dead, but didn't work very well. I "refurbished" them by filling a squirt bottle with brake fluid, inserting it into the vacuum line, and operating the wiper blades manually. It helped a lot.

Bur remember, it is brake fluid and can do a lot of damage to paint, so be careful if you do this.

[Zeke3]

If I thought there was an issue with the vacuum side of the system, I would use a vacuum gauge to check the vacuum at the intake manifold connection with the engine idling. Next, check the vacuum available to the switch and finally check the vacuum available to the motor, switching the switch off and on. This should locate whether there is an issue with the vacuum circuit or the motor itself.

[Zax40]

Check the vacuum line going into the wiper vacuum "motor". Should have vacuum at idle and increase with throttle. Could be the line is old and not sealing or has fell off the inlet. The knob should be cable or linkage activated and move a small slide at the top of the wiper motor. You should be able to hold your finger on it and feel it slide it in and out with someone working the knob to test. Next check the wiper arms that go to the transmissions/towers and make sure they move freely and are not binding. If all that checks out remove the vacuum wiper motor and check and make sure it moves freely. If it is stuck sometimes a couple squirts of WD40 will break it loose. You should feel the resistance of the vacuum but it should not have any sticky spots. If it is too loose your rubber seals may be worn inside.They are not too hard to take apart and clean and inspect. Just be careful with the tiny screws. I used a dollar store baking pan like I do when I take apart carbs so none of the tiny pieces get lost.

[Karl]

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All good suggestions here which may work . My experience is that if these measures don't work the most likely thing is that the diecast housing is warped and hence you will never get a good seal on the "flapper" no matter what you do -Karl