I watched the short video on that pump and it seems to run a bit noisy. Not sure I would want that sound under the dash. I would probably put it in the engine bay somewhere. But then again they just had it sitting on the table too.

 

That's 16" of mercury. A typical engine's manifold vacuum is well above that at idle, maybe 13" at cruise. Depends how hard the engine is working (how far open the throttle is).

I don't see where that lists a pressure rating? The kind of pump needed for the wipers has to have a lot of volume. The factory-style dual diaphragm fuel pump was ideal.

 

Ah yes, the periodic table! Thanks It does list the PSI under the specs.

 

got it apart and back together. Works great and pulls 18" when run off the 6V battery.






from what i can tell it has a cut out switch that is adjustable so its not running unless the vacuum drops below the set point. ill put it back in the truck sometime and see what i can do. if thats the case i can likely get by with running in on 12v because it will be running intermittently. a look at the inside windings and it was like new with stout wiring

 

Nice clean job!

 

My 226 can easily pull 16"Hg vacuum. That little pump may pull 16"Hg of vacuum but at what flow volume? Certainly not what 6 or 8 cylinders can pull. A reservoir I would bet would definitely be required.

 

We bought 5 new 1955 B700 Superior buses all had electric/ vac because the body
mfg. installed two vac wiper instead of one. I wonder why, many vehicles at that
time had electric wipers - Big Jobs had electrics.

 

Then perhaps a larger pump. I'm not trying to sell or push any particular pump. I chose to show that one because of the very low cost. If it's not up to the task, go bigger. My original question still stands. Could the vacuum wiper issues be resolved with an inline pump? Knowing the amount of vacuum required, would, of course, be a help. It just seems to me, an inline pump would quickly and finally resolve a lot of issues.

 

Many volkswagens used supplemental vacuum pumps for the brakes, they are all over ebay for under $50 shipped. I have a couple here and was going to try one as a supplement to the vacuum wipers on my 37 buick and 47 caddy. They are not very big and can be hidden pretty easily.

 

I think a pump might work well as long as it has the volume and vacuum capacity. I'm not familiar with the volume of vacuum required for the wipers (I switched to electric) but I would think it wouldn't be all that much unless there is some leakage involved. I think they have vacuum pumps for power brake units that are used on muscle cars that have high performance camshafts which won't allow high enough vacuum (due to valve overlap) and need an auxiliary source. Perhaps one of those are just the ticket.

 

I'm going to see if I can locate something cheap enough to experiment with. It can't be that difficult to route the pump and my neighbor just pulled a vac reservoir from his 51 sedan, (with a chiby SB). I'm thinking putting that plastic ball between the pump and the wiper actuator would be just the ticket needed.

 

I don't want to discourage you but I believe the small ball reservoir will not provide much help. Those reservoirs are designed to move small HVAC motors one time where the windshield wiper motor operates constantly and uses lots of air volume. I figures out about how many cubic inches the motor used but no longer have those figures. I built a 4" X 5' reservoir from PVC pipe. It seems to help some but I've not had chance to really test it. Please report back when you have a chance to test it. If you have a good steady vacuum source, these wipers can work very nicely.

 

What would make an excellent reservoir is a small portable air tank. That's what I intend to use.

 

RAY where are you planning to hide a 5 foot pipe?

 

That's a good point. The constant need for draw may be more than the ball can handle. If you could evacuate a four inch by five foot piece of pvc you would most certainly have constant draw. However, it would take up some bed space! The more I think about this, the more I am convincing myself it wouldn't be cost effective and I can replace the whole thing with an electric for a lot less, as opposed to the other way around.
In all the vehicles I have had with vac wipers, I have never had one that operated well by any modern standard. Even my 53 business coupe was only 11 years old when I got it and the wipers still had the same issues then, as today.