The Stovebolt Site Forums The Shop Area General Truck Talk Vacuum wiper normal operation?

I have a '49 3100 with what i believe are the original vacuum powered wipers. I've always had to move the wiper switch back-and-forth manually - to one side to get them to go one way, and then to the other side to get them to go back. I just assumed that was the way these old things worked. I was at a car show this past weekend and a guy told me the wipers should go back-and-forth without having to continually move the switch. Is that information correct, and if so, does anyone have an idea why mine would work the way they do?

Thanks,
Greg

Wiper should go back and forth without you having to constantly move the switch. Poor vacuum to motor or motor needs rebuild.🛠

yes, they should go back and forth. Your vacuum motor may be gummed up, and/or all dried out. Make sure you have good vacuum lines going to it with no leaks, pull the motor apart and clean and lube everything, and put it back together (make sure there are no vacuum leaks). When you turn it on, you are not getting enough vacuum to move the wipers all the way up and then back down so, they stall. ONce you turn the switch back off, it pulls it back into "park" and returns the wipers to the "park" or "home" position.

Thank you guys for the quick reply. I'm pretty sure I have adequate vacuum going to the motor, so it looks like I have another project for the list...

Thanks again,
Greg

The vacuum motor has a little switch that is activated at the end of it's travel. It switches the feed to the other side of the paddle. If that valve hangs up, it will act just as you described. I have an NOS unit for my 38 and it was doing that. I freed up the valve and it works perfectly.

Thank you. That's very helpful and what I was hoping to learn.

Look for an open port on the wiper motor that sticks out enough to attach a piece of vacuum hose. Rig up a Coke bottle of Diesel fuel with a short pierce of hose in it, turn on the wipers, and let the vacuum draw the liquid through the motor. It will clean and lubricate the wiper motor without ever having to remove it from the vehicle, and the Diesel will go through the intake manifold and clean and lubricate the valve guides before being burned in the combustion chamber. We used to use 6-ounce cans of Aviex tune up oil to rehab wiper motors that way, but Diesel will do the same job.
Jerry

After cleaning/freeing it up, here are the best ports/holes for applying lubricant.

Here is an excellent rebuilder.
Here is his rebuild process/steps.

This is a great example of the value of these forums. Old timer tricks like this are priceless.

Not all vacuum wiper motors will have that nipple, but on the ones that do, it's a quick, easy fix. The solvent gets drawn through the motor, and cleans and lubricates all the moving parts. Then it gets drawn into the intake and burned- - - -no muss, no fuss! On the ones with the tiny intake holes instead of the nipple, spraying WD-40, PB Blaster, or KROIL into the vent with the motor running will accomplish the same thing.
Jerry