Vacuum wipers

[Zeek]

I have a 1952 M37 with vacuum wipers, of course they do not work. I need to know how many inches of vacuum it takes to make the wipers work.
Thanks for any help.

Zeek

 

[AN/GRC-46]

Difficult to answer such a simple question. One 1950's automotive source I've seen said 7-13". Another source said a minimum of 17". A Trico repairman implies they should work at 13". One big variable is the pressure of the blade on the windshield - too much will put too much drag on the system, too little pressure will result in insufficient wiping action. When all is said and done, I would say 13" should work, especially since the blades and arms aren't designed to put too much pressure on the glass. To lessen the drag, I use RainEx on the glass.

Another variable is what lubrication is used on the paddle blades inside the motor. Some people use white grease, Vasoline, engine oil, sewing machine oil, WD-40, or any number of other lubes. You need something that is adherent enough to stay in place, but not so thick that it'll slow the works down. A light coat of Silicone grease seems to work well.

 

[98taco3]

has anyone rebuilt these themselves? The TM has instructions and ive found repair kits. Fairly easy to do?

 

[dodgedougak]

98taco3- Keep us informed how it goes. I need to OH the wipes on my M38A1. The ones on my M37 were changed to electric, long ago. Good Luck

 

[Oldfart]

I put electric wipers on my M37 a long time ago. I would struggle to get them working in Denver and then a trip to the mountains they would just quit. It was hard to get them both working at the same pace as well. Usually had to just use the drivers side when I went to higher altitudes and even then they were a problem. I even added a vacuum booster pump for a while trying to get them to work better. Even after a overhaul and fresh lubricant, they would quit working on a long haul up grade at altitude. I saw an M37 that had converted to air motors off a deuce. He had installed a deuce compressor and air tanks and the air wipers worked great.

Yes, I have taken mine apart and put them back together several times. It is not rocket science. The lubricating /sealing agent does make a difference, wiper blade pressure makes a difference as does blade length. The condition of the vacuum side of the fuel pump makes a difference as does ignition timing and engine manifold vacuum.

I have seen people struggle with the vacuum wipers not knowing the guy before them put in a replacement fuel pump that was single action and then just plumbed the wipers direct to engine vacuum. I have also seen lots of M37 wipers with broken assist handles where someone tried to operate them manually and over loaded the handle.

 

[98taco3]

hmm, ill have to pull them apart. One feels great and still moves smoothly but the other is seized up. Electric wipers are in the cards for it eventually but theres more important things that need done first.

 

[Oilleaker1]

Yes, they are not going to work going up a hill with the throttle opened up, you lose your engine vaccum. The double fuel pump will help, but they still almost stop. You just let off the throttle, wipe accross, and get back into the throttle or use your hand. Downhill is great! Be very careful of the gasket when you lift the top off. Study the spring mechanism before you take it apart. Clean the old gummed crap with parts cleaning solvent, and then put a nice light coat of thin chassis grease on the surfaces, rubber wiper, and the control handle surface where the air is shut on and off. Too thin a grease it leaks by, too thick it won't move. They are part of the flavor of owning a piece of history. Otherwise, put in a cummins diesel, and 12 volt electric wipers, and big mudder swamp tires John ( whatever turns your crank )

 

[majorhitt]

Keep in mind too, Every place you make a connection from hard tubing to flex tubing you have the potential for leaks. Make your connections leak proof.

 

[Zeek]

Thanks for all the info. Its a great help

98Taco3 where did you find the rebuilding kits?

Zeek

 

[Oddball-CmK]

Vacuum Wipers

Zeek,

If interested and feel like taking the simpler approach, I have N.O.S vacuum wipers I could sell you (see pictures).

Cordell

 

[Oddball-CmK]

Sorry, I have decided to keep the above wiper motors for now as I have found an application I can use them on...

 

[Zeek]

Oddball CmK - thanks for the offer. Let me know what you want for them. I do have the wiper motors, didn't have the vacumm pump. I now have the pump and want to see if I can get mine working. If not, I will get in touch with you for a possible sale.

Thanks Zeek

 

[Zeek]

Oddball CmK - Thats fine thans for the reply.

Zeek

 

[AN/GRC-46]

Regarding the original question, I measured my vacuum and have 18" at the wipers.