The wipers on my 41 Chevy are vac. and not working right. When they are turned on the knob doesn't seem to move easy, to the right is off to the left is on. It seems like its not moving.It just give you some resistance & snaps right back. when you hold pressure to the on position they come on but go off when released! then sometimes they'll flop 2 or 3 times & stop. Also were should I pick up the vacuum for it? right now its off the manifold behind the carb & the hose goes to the power brake booster also. Is the "switch" actually just a valve that opens? And should the vac line be dedicated to just the booster? Thanks
Sounds like a lack of lubrication and maybe worn seals. These vacuum motors tend to get dried out internally over time, sometimes just a disassembly/cleaning/relubing them will restore performance. As far as a vacuum source, where you have it is as good as it gets (the booster will act as a reservoir) unless the OEM install used a dual-diaphragm fuel pump, with the top half being an auxiliary vacuum pump. But it depends on how much engine vacuum is available at 'normal' speeds. Big cams, small motors, all sorts of combinations can effect vacuum....
The switch is a cable that works the wiper switch on the wiper motor. Cable can get gummed up and not operate smooth. Pull the cable at the dash and take it out soak it in PB. Vac. Off the intake is good. You can send the motor off for a rebuild. Right now I cannot remember the name of the company. It's in the North. Maybe I remember it tomorrow.
Don't let anyone fool you. Even when perfect they don't work all that well. When I drove a 54 Chevy a few years ago as my daily it used to scare the hell out of my car poolers when it rained. Get it lubricated, make sure nothing is hard and cracked and then get some rain-X.
Their was some information on here it might be in the tech section on some cork like restriction that are supposed to be in the lines or vacuum hoses that fall out or dissolve,if they are in place the system seam to work like regular wipers.
Don't open it--squirt some brake fluid in through the inlet and the seals may soften up. Vacuum wipers are super fun, especially when passing or going up hills at night.
I take off the hose to the motor and replace it with a short piece. I then put about 15 drops of 3 in 1 oil in the short hose and let it drain into the motor. After letting it set for a while, I replace the original hose and start up the car. I then proceed to wash the car and while wetting it with the hose, I have the wipers running. It kind of wakes them up for the cruising season. They are still not perfect as others have mentioned, but they do work.
Do yourself a favor, and replace that vacuum motor with an electric one. At their best, the vacuum wiper motors were pieces of shit. I owned several cars that were equipped with them, and every one performed poorly. Step on the gas to negotiate an uphill grade, and they stop. Downhill grade, and they go like hell. A safety hazard to be sure. I'm guessing that they were cheaper to produce than an electrically operated unit, so the manufacturers went with the less expensive vacuum units. Even if an electric wiper motor is "non-traditional", I'd still swap it out with something reliable. Your safety trumps traditional in my opinion. Wayne
Newport Engineering makes the best bolt in motors. I have two cars with them currently and have installed several others.
Changing to an electric motor could be your best solution......in the old days here in the moist PNW we put a vacuum reservoir into the system, hence no more lack of vacuum when going up a hill......made one out of a stainless thermos core once, just brazed in fittings to run lines....
The main issue was electrical power, or the lack of it. Most 'vintage' generators only put out about 30 amps, a six volt wiper motor could easily draw well over ten amps. Add in ignition, lighting, heater fan, and maybe a radio and you would run out of power.
You can use an alternator off a Jap diesel, they have a vacuum pump on the back of them. But you'll need to plumb in an oil feed and return. This cures your charging /vacuum issues in one go! But if you want to keep your vacuum wipers "old timer authentic" and it has a vacuum tank, go and vulture a 12 volt vacuum pump off a late VW or Audi, and plumb/wire it into the system [you can hide this anywhere]. Put a 1-way check valve in the engine vacuum line, and a vacuum switch in the tank. When the engine vacuum drops off, the electric vacuum pump pulls the vacuum. It'll only draw power on demand The VW Audi pump is good enough for boosted brakes I am presently experimenting with a vacuum pump and brake booster on a trailer with surge brakes [ I am trying to reduce the weight transfer into the tow vehicle ]
What this guy said I put a vacuum reservoir off a 90's model Ford F-150 on mine. I haven't had any problems when going up hill or taking off from a stop or red light.
Toyota Forerunner haS a vac pump/alt, but a lot (if not all) diesel pick-ups, 4 WD, even sedans should have something you can use. I squirted a little ATF down into the vac pump, worked it by hand a few times and then hooked up a "vaccuum tank" which the lumpy-cam brigade use, and it works fine. These have a non-return valve in them the same as a power brake booster. If your switch is like the later (46 onwards) Chevy (mounted near the windscreen with 3 vac.lines ), it will have 3 connections- vac, run and park. They are a simple valve, but can leak , resulting in your engine running a bit rough.
All Mitsubishi 4D56 and 4M40 powered vehicles [L200, L300, Montero's] All Toyota 2L ,3L , 1Kz , 1C, 2C, 3C [ Hilux's Hiace Vans, Camry's, Cressida's, Corona's] All Nissan CD17, CD20, RD20, LD20, LD28, SD20, TD20, [ Navara's, 720's, Bluebirds, AD wagons ] Common as shit outside the USA The Nissan is more reliable than the Mitsy [which has a reputation for stripping the drive spline to the pump] They are all internally regulated In the USA the best bet would be an Alternator off an Isuzu 4BD1-T commonly found in a NPR or NKR truck. [they are 12 volt in the USA but 24 volt over here]
I like them, kinda cool, they work at least for me. Might try Rainex, that stuff helps with any wipers. Many optional fuel pumps of the era had provisions to work the wipers.
I have repaired vacumn wipers with absolutely no problem doing so. The old grease inside gets hard and restricts the paddle from sweeping back and forth freely,taking it apart is not rocket science,clean the housing,and the paddle,use a thin coating of grease,make a new cork gasket if possible and put it all back together,always make sure the rubber hose connections are not brittle and the fixed hard line tubing is unobstructed. BTW,Rain-X is the hot rodders friend. HRP
My thoughts on this exactly. My '51 Hudson has vacuum wipers that work on a dual action fuel pump. As mentioned earlier it has a vaccum pump on the top half to run the wiper motor. It works decent but only when it's actually raining and the windshield is wet to give the wipers some lube. Otherwise they won't even go all the way across the windshield. I am a huge fan of Rain-X.
A few years ago I had a friend with the same problem, very weak vacuum wipers. We found a small vacuum pump at a marina boat supply and piped it directly to the wipers using a vacuum canister found in some GM cars. We left the original vacuum circuit intact, not to disturb the vacuum advance or other vacuum controlled items and controlled the pump with a toggle switch. I can't begin to tell you how great it worked. I know they make vacuum pumps for cars with big cams and blowers but the pump we found was perfect.
my 41 olds is vac and had same problem. make sure you have tight fitting hose take the unit out 2 screws and spray wd 40 in it and let it set a couple days spray in again and work it back and forth again let it set then spray again I hooked the vac tube back up to it and worked good. make sure you clean and lube the arms when you put them back on, and the rainex does make it move easier across the glass.
Why, because you don't know how to do wiring and have an abnormal fear of electrons ? You said to school you, and the lesson that makes the most sense is being ignored That lesson is, yank out that old vacuum stuff and go with a conversion kit from Newport Engineering. But you know what they say, you can lead the horse to the water but ...
If you go for an electric bolt-in job, some won't go in unless you remove the radio. Not a big deal, but the radio kinda looks neat in the dash . You could remove the "guts" and just leave the faceplate on.
Lot of good info above. pretty simple to take apart and like above, the grease does get hard..i used white lithium grease to replace the old hard stuff. the brake fluid, squirted in where the vacuum line hooks up, swells the seals. will last for a while then you will have to do it again. I did this for years on my 56 chebby , till I found electric. you can make them run, but I like electric. JMO Good luck. and buy lots-o-rain-x.
Mentioned above were late model Audi or VW electric pumps. Can I get more specifics so that I can try to locate one around here? Thanks
in the trunk of my pontiac I found a metal Reservoir ( size of a tomato juice can ) and a vacuum check valve ( ford part) both look like they came off one of old t-birds my dad had with the headlight doors , the tag they ( P.o.) put on it said it was for the wiper system . the Pontiacs had the fuel/vacuum pump maybe this was a helper the P.O. engineered .
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