Weak Wiper problem solved!

bigd1101

bigd1101

Senior Member
Well folks, the guy who rebuilt the flathead was right. The PVC valve I installed was robbing the wipers of vacuum. I pulled the PVC hose off the "T" where is fed into the vacuum that fed the wipers, the power brakes, etc. and started the car up.......and sure enough, the wipers work like new, or at least new for a 70 year old car :) and something here in NYS has to work for the yearly inspection.

My new problem is: How can I keep the PVC valve in place as they do serve a good purpose (debatable here I'm sure) and.....keep the proper vacuum to the wipers? Or is it an either/or?

Don
 
You probably need a 'vacuum cannister' to store vacuum - with a one-way valve in the line. This way, the vacuum can be increased, but not decreased . . . which gives you some stored capacity.

With that said, if you're under load, the vacuum will drop, and the reservoir will get depleted - which is pretty much the issue with vacuum-based wipers in the first place.

The only way to solve that issue is to install some sort of add-on vacuum pump.
 
The best step is to move the vacuum to another source. What year is your car? 70 year old implies a 50s car. Now if it was a 30s car, you could add a vacuum under the carb in addition to the vacuum port at the valves. Ford had some fuel pumps with a vacuum port in the 50s if I recall, but I don't know if they fit your car.
 
Juergen said:
The best step is to move the vacuum to another source. What year is your car? 70 year old implies a 50s car. Now if it was a 30s car, you could add a vacuum under the carb in addition to the vacuum port at the valves. Ford had some fuel pumps with a vacuum port in the 50s if I recall, but I don't know if they fit your car.
Click to expand...

53 Merc (pictured)
 
If you don't have one already get a stock duel diaphragm fuel pump. It will give you the added vacuum you need. After that add the carb spacer with a designated PVC port. I think you will be very happy with the results. Tim
 
Maybe I just re-install the old block vent tube and scrap the PVC valve......at least to get it to pass NYS inspection. :)
 
I had the same problem with the vacuum wipers on my 51 after going to PCV. My solution was the New Port Engineering electric motor. Works great as long as you are running 12V... Ken
 
bigd1101 said:
Well folks, the guy who rebuilt the flathead was right. The PVC valve I installed was robbing the wipers of vacuum. I pulled the PVC hose off the "T" where is fed into the vacuum that fed the wipers, the power brakes, etc. and started the car up.......and sure enough, the wipers work like new, or at least new for a 70 year old car :) and something here in NYS has to work for the yearly inspection.

My new problem is: How can I keep the PVC valve in place as they do serve a good purpose (debatable here I'm sure) and.....keep the proper vacuum to the wipers? Or is it an either/or?

Don
Click to expand...
Thanks for posting your resolution, very helpful.
 
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