The Ford Barn

shew01 · 04-10-2022, 02:27 PM

I got caught in the snow while driving my Model A this weekend, and my vacuum wiper was not up to the task of clearing the windshield. It’s always been weak since I bought the car a couple of years ago, but this time it couldn’t clear the snow flurries on the windshield at all. So, the flurries just bunched up on the windshield and turned into ice.

At this point, I don’t know if I have a leak in the line from the intake manifold, or if I have a bad wiper motor. I searched on this site, but I didn’t find anything useful for debugging this issue.

I don’t know much about the vacuum system. Can anyone give me some ideas how and what to check? Thanks in advance.

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nkaminar · 04-10-2022, 02:33 PM

The link below shows how to add light oil to the wiper motor. Basically you put the vacuum line in some oil and suck it into the motor by moving the wiper back and forth. There are also some discussion about the different vacuum motors and overhauling them.

http://modelabasics.com/wiper.htm

Don't use WD-40 as it will eventually evaporate. 3 in 1 oil is what I would use. If this does not work, look for where the air enters near the on/off valve, not where the vacuum fitting is, and squirt some light oil in there while it is operating.

If oiling fails you will have to take it apart and overhaul it. There are instructions on the web or you could send it to someone.

gdmn852 · 04-10-2022, 03:11 PM

The vacuum wipers are problematic, why they used them up into the 60,s on some cars, Rambler was one , stop going uphill or passing, in super sonic mode down hill. Had a 41 Packard that had 2 speed electric that actually worked so even then the technology for electric wipers existed.Sometimes if you have a reserve tank may work better, My roadster was fitted with an electric, but that small wiper blade on flat windshield isn’t the most efficient setup. Most people use a Rain X , that helps.Not being used much probably adds to the problem.

Oldgearz · 04-10-2022, 04:07 PM

I've used a 12" length of vacuum line (clear poly so you can see inside) filled with MMO and attached to the vacuum fitting. First, take off your vacuum line at the fitting and manually move the wipers back and forth. You will feel wiper is either blowing or sucking air at the fitting. Stop after a blowing movement and attach the hose filled with MMO. Then, with the far end of the hose uncovered, rapidly move the wiper all the way it will go. Put your finger over the hose end and return wiper slowly to the reverse position. Then uncover the end and rapidly move the wiper back through its sucking cycle. Do this several times until the hose is empty of MMO. You may have to do this 2-3 times. If this doesn't lube and seal the inards, you'll have to take it apart.

Gene F · 04-10-2022, 04:41 PM

Electric is the way to go. The supply houses now sell a setup that still allows the windshield to open.

McMimmcs · 04-10-2022, 05:23 PM

Sponsored Links (Register now to hide all advertisements)

I am sure you have good reason to drive your A in the snow but You might also be concerned about the damage the road salt is doing to your car’s body.

shew01 · 04-10-2022, 05:56 PM

Quote:

Originally Posted by McMimmcs

I am sure you have good reason to drive your A in the snow but You might also be concerned about the damage the road salt is doing to your car’s body.

Re-read the post. I got caught in the snow. The forecast was for clear weather. I don’t intentionally drive the car in the rain, let alone in the snow.

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shew01 · 04-10-2022, 07:20 PM

Quote:

Originally Posted by nkaminar

The link below shows how to add light oil to the wiper motor. Basically you put the vacuum line in some oil and suck it into the motor by moving the wiper back and forth. There are also some discussion about the different vacuum motors and overhauling them.

http://modelabasics.com/wiper.htm

Don't use WD-40 as it will eventually evaporate. 3 in 1 oil is what I would use. If this does not work, look for where the air enters near the on/off valve, not where the vacuum fitting is, and squirt some light oil in there while it is operating.

If oiling fails you will have to take it apart and overhaul it. There are instructions on the web or you could send it to someone.

Thanks for the link. That looks very helpful. :-)

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shew01 · 04-10-2022, 07:22 PM

Quote:

Originally Posted by gdmn852

The vacuum wipers are problematic, why they used them up into the 60,s on some cars, Rambler was one , stop going uphill or passing, in super sonic mode down hill. Had a 41 Packard that had 2 speed electric that actually worked so even then the technology for electric wipers existed.Sometimes if you have a reserve tank may work better, My roadster was fitted with an electric, but that small wiper blade on flat windshield isn’t the most efficient setup. Most people use a Rain X , that helps.Not being used much probably adds to the problem.

My dad had a 1966 Rambler Classic. As I recall, it had vacuum wipers. We thought it was neat because you could adjust the wiper speed.

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shew01 · 04-10-2022, 07:23 PM

Quote:

Originally Posted by Oldgearz

I've used a 12" length of vacuum line (clear poly so you can see inside) filled with MMO and attached to the vacuum fitting. First, take off your vacuum line at the fitting and manually move the wipers back and forth. You will feel wiper is either blowing or sucking air at the fitting. Stop after a blowing movement and attach the hose filled with MMO. Then, with the far end of the hose uncovered, rapidly move the wiper all the way it will go. Put your finger over the hose end and return wiper slowly to the reverse position. Then uncover the end and rapidly move the wiper back through its sucking cycle. Do this several times until the hose is empty of MMO. You may have to do this 2-3 times. If this doesn't lube and seal the inards, you'll have to take it apart.

When I get a chance, I plan to try this. Thanks for posting.

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Colonial coupe · 04-11-2022, 05:54 AM

My vacuum wiper function really improved after I did a valve job on my engine. Put a good vacuum gage on your vacuum port and check engine vacuum. Your wiper may be telling you something.

rotorwrench · 04-11-2022, 10:11 AM

If your wiper is a slug a bug under normal conditions then it may need an overhaul of the flap seal and gasket replacement. If it functions normally during moderate temperatures then the problem could be the cold weather. Parts contract and stiffen in cold weather so that doesn't help function. If it functions better when you let off the throttle then the operator has to go under power for a bit then let off the throttle for a bit to clear the windshield. This has always been an issue with vacuum wiper motors. In later years, dual action fuel pumps were offered to boost the vacuum while the engine is under load. This helped quite a bit but these fuel pumps were an option and not standard equipment in more arid regions of the country.

As was mentioned, engine ring & valve condition can have an affect on the manifold pressure. Higher than normal manifold pressure would cause problematic wiper motor function.

KGBnut · 04-11-2022, 12:25 PM

Those wipers are awfully tricky...finicky tolerances...non-standard fasteners. I did the best to get mine working correctly, but had little luck. I ended up sending it out for a rebuild. That was twelve years ago and it still works great. I sent it to Ficken. The price was reasonable, and the turn-around time was pretty quick.

https://rebuildingtricowipers.com/

Ken

gary678* · 04-11-2022, 01:13 PM

From what I have read and after talking with experienced "A"ers the vacuum wipers are best used as an ornament. Rainex is the way to go and I would assume that the Rainex would not allow the flurries to accumulate, but that's a guess as I have never driven my A in snow.

shew01 · 04-11-2022, 04:31 PM

I thought I’d start testing at the easiest point. I didn’t know if I have a leak in the line between the intake manifold and the wiper motor; so, I connected a vacuum gauge at the wiper end of the line, and I am getting around 18 on the gauge. Here is a picture of it. I didn’t see a way to upload video. Does this look typical? The engine is cold. I don’t know if that makes a difference or not.

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shew01 · 04-11-2022, 05:09 PM

Neal, Oldgearz,

I put some Marvel Mystery Oil in a small squirt bottle and blew a little into the wiper motor vacuum fitting, and I replaced the 3” long vacuum line between the wiper motor and the line that comes through the header. Wow. I have a wiper now (at least in the dry), although the wiper still may end up being mostly decorative in the rain. Lol

This a HUGE difference. Thanks for your help! [emoji3]

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04-10-2022, 02:27 PM	#1
shew01 Senior Member Join Date: Sep 2016 Location: Roanoke, VA USA Posts: 1,908	Weak Wiper I got caught in the snow while driving my Model A this weekend, and my vacuum wiper was not up to the task of clearing the windshield. It’s always been weak since I bought the car a couple of years ago, but this time it couldn’t clear the snow flurries on the windshield at all. So, the flurries just bunched up on the windshield and turned into ice. At this point, I don’t know if I have a leak in the line from the intake manifold, or if I have a bad wiper motor. I searched on this site, but I didn’t find anything useful for debugging this issue. I don’t know much about the vacuum system. Can anyone give me some ideas how and what to check? Thanks in advance. Sent from my iPhone using Tapatalk

04-10-2022, 02:33 PM	#2
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: Weak Wiper The link below shows how to add light oil to the wiper motor. Basically you put the vacuum line in some oil and suck it into the motor by moving the wiper back and forth. There are also some discussion about the different vacuum motors and overhauling them. http://modelabasics.com/wiper.htm Don't use WD-40 as it will eventually evaporate. 3 in 1 oil is what I would use. If this does not work, look for where the air enters near the on/off valve, not where the vacuum fitting is, and squirt some light oil in there while it is operating. If oiling fails you will have to take it apart and overhaul it. There are instructions on the web or you could send it to someone. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 04-10-2022 at 05:31 PM.

04-10-2022, 03:11 PM	#3
gdmn852 Senior Member Join Date: Feb 2019 Location: Erie Pa Posts: 689	Re: Weak Wiper The vacuum wipers are problematic, why they used them up into the 60,s on some cars, Rambler was one , stop going uphill or passing, in super sonic mode down hill. Had a 41 Packard that had 2 speed electric that actually worked so even then the technology for electric wipers existed.Sometimes if you have a reserve tank may work better, My roadster was fitted with an electric, but that small wiper blade on flat windshield isn’t the most efficient setup. Most people use a Rain X , that helps.Not being used much probably adds to the problem.

04-10-2022, 04:07 PM	#4
Oldgearz Senior Member Join Date: Aug 2020 Location: Sagle, Idaho Posts: 359	Re: Weak Wiper I've used a 12" length of vacuum line (clear poly so you can see inside) filled with MMO and attached to the vacuum fitting. First, take off your vacuum line at the fitting and manually move the wipers back and forth. You will feel wiper is either blowing or sucking air at the fitting. Stop after a blowing movement and attach the hose filled with MMO. Then, with the far end of the hose uncovered, rapidly move the wiper all the way it will go. Put your finger over the hose end and return wiper slowly to the reverse position. Then uncover the end and rapidly move the wiper back through its sucking cycle. Do this several times until the hose is empty of MMO. You may have to do this 2-3 times. If this doesn't lube and seal the inards, you'll have to take it apart.

04-10-2022, 04:41 PM	#5
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 1,973	Re: Weak Wiper Electric is the way to go. The supply houses now sell a setup that still allows the windshield to open.

04-10-2022, 05:23 PM	#6
McMimmcs Senior Member Join Date: Sep 2019 Location: Fort Gratiot, Michigan Posts: 2,296	Re: Weak Wiper Sponsored Links (Register now to hide all advertisements) I am sure you have good reason to drive your A in the snow but You might also be concerned about the damage the road salt is doing to your car’s body.

04-11-2022, 05:54 AM	#11
Colonial coupe Member Join Date: Oct 2019 Location: Southeast Virginia Posts: 42	Re: Weak Wiper My vacuum wiper function really improved after I did a valve job on my engine. Put a good vacuum gage on your vacuum port and check engine vacuum. Your wiper may be telling you something.

04-11-2022, 10:11 AM	#12
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: Weak Wiper If your wiper is a slug a bug under normal conditions then it may need an overhaul of the flap seal and gasket replacement. If it functions normally during moderate temperatures then the problem could be the cold weather. Parts contract and stiffen in cold weather so that doesn't help function. If it functions better when you let off the throttle then the operator has to go under power for a bit then let off the throttle for a bit to clear the windshield. This has always been an issue with vacuum wiper motors. In later years, dual action fuel pumps were offered to boost the vacuum while the engine is under load. This helped quite a bit but these fuel pumps were an option and not standard equipment in more arid regions of the country. As was mentioned, engine ring & valve condition can have an affect on the manifold pressure. Higher than normal manifold pressure would cause problematic wiper motor function.

04-11-2022, 12:25 PM	#13
KGBnut Senior Member Join Date: Jul 2011 Location: Southwestern Connecticut Posts: 931	Re: Weak Wiper Those wipers are awfully tricky...finicky tolerances...non-standard fasteners. I did the best to get mine working correctly, but had little luck. I ended up sending it out for a rebuild. That was twelve years ago and it still works great. I sent it to Ficken. The price was reasonable, and the turn-around time was pretty quick. https://rebuildingtricowipers.com/ Ken __________________ Style beats speed any day, and with a lot fewer tickets.

04-11-2022, 01:13 PM	#14
gary678* Senior Member Join Date: Dec 2016 Location: Middletown, NY Posts: 165	Re: Weak Wiper From what I have read and after talking with experienced "A"ers the vacuum wipers are best used as an ornament. Rainex is the way to go and I would assume that the Rainex would not allow the flurries to accumulate, but that's a guess as I have never driven my A in snow.

04-11-2022, 04:31 PM	#15
shew01 Senior Member Join Date: Sep 2016 Location: Roanoke, VA USA Posts: 1,908	Weak Wiper I thought I’d start testing at the easiest point. I didn’t know if I have a leak in the line between the intake manifold and the wiper motor; so, I connected a vacuum gauge at the wiper end of the line, and I am getting around 18 on the gauge. Here is a picture of it. I didn’t see a way to upload video. Does this look typical? The engine is cold. I don’t know if that makes a difference or not. Sent from my iPhone using Tapatalk

04-11-2022, 05:09 PM	#16
shew01 Senior Member Join Date: Sep 2016 Location: Roanoke, VA USA Posts: 1,908	Weak Wiper Neal, Oldgearz, I put some Marvel Mystery Oil in a small squirt bottle and blew a little into the wiper motor vacuum fitting, and I replaced the 3” long vacuum line between the wiper motor and the line that comes through the header. Wow. I have a wiper now (at least in the dry), although the wiper still may end up being mostly decorative in the rain. Lol This a HUGE difference. Thanks for your help! [emoji3] Sent from my iPhone using Tapatalk