Stovebolt.com Forums The Shop Area The Engine Shop dual action fuel pump

I had in mind to buy a dual action fuel pump to drive my vacuum wiper motor. I found part numbers for them, and then found them listed many places on the internet. But, everywhere I looked they were out of stock. This leads me to believe that the demand for them has dropped off so much that they've probably quit making them. Can one of you guys point me to someplace where I can buy one.

You should be aware that a dual action pump is not a substitute for manifold vacuum- - - - -it's plumbed inline between the intake manifold and the wiper motor to assist, not substitute for intake vacuum. The pump takes over and keeps the wipers running- - - -sort of- - - -when you open the throttle to pass or climb a hill, and the vacuum in the manifold virtually goes away. About the only thing you'll be able to find these days will be a 3rd. world "rebuilt" unit- - - -new ones haven't been made in a couple of decades, at least. The reason they're so scarce is a lack of rebuildable cores.
Jerry

1.) Regardless of the comments of injected restorative liquids like diesel oil, brake fluid or moonshine, to make the old vacuum motor work, send your Trico motor to Ficken Wiper Service (www.wiperman.com [wiperman.com]). This will solve the internal vacuum leakage and get you back to square one.

2.) A quote from a VCCA member (Junkyard Dog), "I have installed about three new dual action fuel pumps on my car (since 1960) and all three were the same.....almost no wipers going up hill. With normal driving, the wipers do work better with a dual action fuel pump than with a single action pump, but going up hill is another story."

Used dual action fuel pumps can still be found and they can be rebuilt, with new hand made kits, to handle modern Ethanol gasoline. The vacuum section can be rebuilt but new (not NOS) kits can be hard to find and are limited to a few AC models (No Carter fuel pumps). Progression: AC 9126 replaced by AC 4138 replaced by AC 4666.

3.) The last add-on, period correct, solution was the Trico Electro-Vac. A little difficult to find today. It is an electric motor driven vacuum pump and reservoir that maintains vacuum level. The irony is, why add an electric motor when you can convert to electric wipers. On a side note, there has been discussions to make a DIY vacuum reservoir using a modern brake booster motor.

Well, I just learned quite a bit about dual action pumps. I had always assumed that having a seperate vacuum pump solved all of the old issues. It's proof that your're never too old to learn. THANKS!! As an alernative to a dual action fuel pump, I had also thought that I'd just buy a 12 volt vacuum pump and use it instead of engine vacuum. I remember reading something about that here somewhere on here a while back.

I bought a brand new AC/Delco dual action pump around 1970 thinking the same thing. As it turned out, it was a great incentive to convert to electric wipers and would have been a decent trot line weight if you had a trot line with only 3 or 4 hooks. Aside from that it was a waste of $ and as others have already said, it was not a solution to driving uphill at all. A couple of years ago I wrote a circuit for adding delay wipers to the AD that used the same switch knob. You end up with low speed, high speed and 4 different speeds of delay wipers. It is still around here somewhere and not difficult to do now that all the work has been done.

Your best way to improve the performance of vacuum powered wipers and other things like 2-speed rear axles, etc. is to install a reservoir tank. Buy a piece of 3" PVC drain pipe and a couple of caps, glue them together, and hide about 3 feet of it inside a frame rail under the cab. Put a rubber grommett and a one way check valve like a brake booster uses into one end cap, and install a screw-in barbed vacuum hose nipple beside it. Then when the vacuum drops, you'll have enough reserve to keep the wipers from stopping. It will also be MUCH less expensive than buying an electric pump.
Jerry

Vacuum wipers work good with a strong V-8 engine. You don't dare get on it hard enough when it's raining to drop the vacuum very much.
George

I bought a NOS vacuum/fuel pump a couple of years back. I don't know why I bought it. It seemed like a good idea at the time. I bought it on ebay and it wasn't enough money for me to remember the cost. It came in the original box I think. I have a 12 volt vacuum pump for my brakes because I have a blower. They can be pricey if you want one that doesn't sound like another engine. I think mine is a scroll type and requires no reservoir but I'll probably put one in anyway. I think it was a little over $500.

I found my vacuum/fuel pump. Turns out I put it on another 292 that I have never started. This is what mine looks like. I'm guessing it wouldn't fit a 235.

I hesitate to show what I drew up 20 years ago or more. Manifold vacuum is essentially a fore pump for the vacuum part of the fuel pump.

It didn't take long for me to convert to electric and I've been happy ever since.