The Ford Barn

gwistrup · 03-11-2023, 08:10 PM

Is there a way to test a vacuum wiper motor? I have a 1940 Tudor Sedan and the wipers don't work. Can I use a Mity Vac hand pump to test it? What typically causes the motor to fail? Can you take the vacuum wiper motor apart to fix it? Thanks in advance.

Ken/Alabama · 03-11-2023, 08:45 PM

Once you get it out you can reconnect it under the hood to the vacuum port and start the engine to test it.

Lawson Cox · 03-11-2023, 09:14 PM

Before doing ANYTHING after you get the vacuum motor out of the car, turn it back and forth with the "arms" to see if there is any resistance, and listen to it to see what it sounds like. There should be slight resistance and a faint sucking sound if it is working. If you still have doubts, get an eye dropper and put three or four droppers FULL of automatic transmission fluid down into the wiper motor and GENTLY move the arms back and forth a few times. (Careful, the ATF fluid will squirt out) Next, set it down somewhere, positioned so that the fluid settles into the lowest part of the chamber, and prop it up so it stays in that position. Get in the bed overnight, get a good night's sleep. Kiss the wife good morning, have a couple cups of coffee, then go back out into the shop, grab the wiper motor, turn it upside down and move the arms back and forth gently, thereby forcing the ATF out. How is the resistance as compared with before? How is the sound? Hold the "tubes" where the vacuum hose attaches to your tongue. Feel any suction from the motor? If so you're probably good to go, but then hook it back up to your engine as Ken suggests and see how it acts. It should be okay. Just donate my fee to T2T.org. Lawson (The paddle inside had dried out.)

SoCalCoupe · 03-12-2023, 12:46 AM

I've heard you can also test it without removing by simply disconnecting the engine vacuum hose from the wiper switch connecting it directly to the wiper motor.

JayChicago · 03-12-2023, 09:45 AM

The wiper switch is part of the wiper motor. No separate switch. The dashboard knob is just a linkage to move the switch on the motor.

On a ‘40, the wiper motor is easy to remove if no radio. If you have a radio, may need to remove radio first, which is a bigger job in itself. Either case, is a laying on your back under the dash board job.

Merc Cruzer · 03-12-2023, 10:48 AM

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I have two ways: the first one, that I have been using forever, is to hook up a air/spray wand to the hose and turn on the compressor. The suction creates the perfect amount of vacuum to operate the wiper.

My second, is when I installed the Electro-Vac unit in the car. It provides additional vacuum, when climbing or accelerating. It will operate the wiper without the motor being on.

FlatheadTed · 03-12-2023, 09:02 PM

use a house hold Vacuum cleaner machine jam the hose in with a lump of rag down the Vac hose . pinch of the hose to regulate it

gwistrup · 03-13-2023, 08:52 AM

Thank you for the replies. If I thought about it, I would have realized that the vacuum motor probably needs at least 10 inches of vacuum to work. That's why the wipers stop working when going up a hill. I don't have a radio so access is easy. I will take it out and give it a dose of ATF to see what happens. If that doesn't work, I will call Ficken Wiper Service.

40ford · 03-14-2023, 07:24 AM

Take the hose off and stick down in a good bottle of marvel mystery oil and slowly work wipers back and fourth and they should draw fluid into motor.re-connect and see what you have now?

gwistrup · 03-14-2023, 09:09 AM

The wiper motor would not budge so I figured I might as well take the top off and look inside. It amazes me how petroleum products such as grease turn into something that resembles peanut brittle after 83 years. I chipped out the solidified stuff inside the housing and cleaned it until it was nice and shiney. I put a light coating of grease on the edge of the flapper thing and after that everything moved nice and smooth. It took me a few minutes to figure out how the little spring and switching valve went back together but I managed to get it. I reduced my shop vac down to a hose small enough to fit on the wiper motor and turned it on. To my surprise, the wiper motor works perfectly now. Thank you for your help. Gil

03-11-2023, 08:10 PM	#1
gwistrup Junior Member Join Date: Jan 2023 Posts: 25	Can you bench test a 1940 vacuum wiper motor? Is there a way to test a vacuum wiper motor? I have a 1940 Tudor Sedan and the wipers don't work. Can I use a Mity Vac hand pump to test it? What typically causes the motor to fail? Can you take the vacuum wiper motor apart to fix it? Thanks in advance.

03-11-2023, 08:45 PM	#2
Ken/Alabama Senior Member Join Date: May 2010 Location: Alabama Posts: 3,261	Re: Can you bench test a 1940 vacuum wiper motor? Once you get it out you can reconnect it under the hood to the vacuum port and start the engine to test it.

03-11-2023, 09:14 PM	#3
Lawson Cox Senior Member Join Date: May 2010 Location: Above the gnat line in Georgia Posts: 7,009	Re: Can you bench test a 1940 vacuum wiper motor? Before doing ANYTHING after you get the vacuum motor out of the car, turn it back and forth with the "arms" to see if there is any resistance, and listen to it to see what it sounds like. There should be slight resistance and a faint sucking sound if it is working. If you still have doubts, get an eye dropper and put three or four droppers FULL of automatic transmission fluid down into the wiper motor and GENTLY move the arms back and forth a few times. (Careful, the ATF fluid will squirt out) Next, set it down somewhere, positioned so that the fluid settles into the lowest part of the chamber, and prop it up so it stays in that position. Get in the bed overnight, get a good night's sleep. Kiss the wife good morning, have a couple cups of coffee, then go back out into the shop, grab the wiper motor, turn it upside down and move the arms back and forth gently, thereby forcing the ATF out. How is the resistance as compared with before? How is the sound? Hold the "tubes" where the vacuum hose attaches to your tongue. Feel any suction from the motor? If so you're probably good to go, but then hook it back up to your engine as Ken suggests and see how it acts. It should be okay. Just donate my fee to T2T.org. Lawson (The paddle inside had dried out.) __________________ Life is like a roll of toilet paper. The closer to the end, the faster it goes. It is better to be seen, than viewed. "We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm".

03-12-2023, 12:46 AM	#4
SoCalCoupe Senior Member Join Date: Sep 2021 Location: Point Loma, San Diego, CA Posts: 424	Re: Can you bench test a 1940 vacuum wiper motor? I've heard you can also test it without removing by simply disconnecting the engine vacuum hose from the wiper switch connecting it directly to the wiper motor.

03-12-2023, 09:45 AM	#5
JayChicago Senior Member Join Date: Jan 2019 Location: Chicago Posts: 732	Re: Can you bench test a 1940 vacuum wiper motor? The wiper switch is part of the wiper motor. No separate switch. The dashboard knob is just a linkage to move the switch on the motor. On a ‘40, the wiper motor is easy to remove if no radio. If you have a radio, may need to remove radio first, which is a bigger job in itself. Either case, is a laying on your back under the dash board job.

03-12-2023, 09:02 PM	#7
FlatheadTed Senior Member Join Date: May 2010 Location: Auckland Posts: 4,705	Re: Can you bench test a 1940 vacuum wiper motor? use a house hold Vacuum cleaner machine jam the hose in with a lump of rag down the Vac hose . pinch of the hose to regulate it __________________ http://www.flatheadted.com Flathead Ted brake Floaters ,

03-13-2023, 08:52 AM	#8
gwistrup Junior Member Join Date: Jan 2023 Posts: 25	Re: Can you bench test a 1940 vacuum wiper motor? Thank you for the replies. If I thought about it, I would have realized that the vacuum motor probably needs at least 10 inches of vacuum to work. That's why the wipers stop working when going up a hill. I don't have a radio so access is easy. I will take it out and give it a dose of ATF to see what happens. If that doesn't work, I will call Ficken Wiper Service.

03-14-2023, 07:24 AM	#9
40ford Senior Member Join Date: May 2010 Location: Cherryville,N.C. Posts: 535	Re: Can you bench test a 1940 vacuum wiper motor? Take the hose off and stick down in a good bottle of marvel mystery oil and slowly work wipers back and fourth and they should draw fluid into motor.re-connect and see what you have now?

03-14-2023, 09:09 AM	#10
gwistrup Junior Member Join Date: Jan 2023 Posts: 25	Re: Can you bench test a 1940 vacuum wiper motor? The wiper motor would not budge so I figured I might as well take the top off and look inside. It amazes me how petroleum products such as grease turn into something that resembles peanut brittle after 83 years. I chipped out the solidified stuff inside the housing and cleaned it until it was nice and shiney. I put a light coating of grease on the edge of the flapper thing and after that everything moved nice and smooth. It took me a few minutes to figure out how the little spring and switching valve went back together but I managed to get it. I reduced my shop vac down to a hose small enough to fit on the wiper motor and turned it on. To my surprise, the wiper motor works perfectly now. Thank you for your help. Gil