Fuel System: Fuel pump with vacuum pump

[dstude]

I just installed one of the optional fuel pumps on my Champion six, one that has the added vacuum diaphragm to create extra vacuum to run the windshield wipers. This is my first experience with one of these fuel/vacuum pumps and I'm curious if I'm hooking it up correctly. The vacuum section has two connections. With the engine running it's obvious which connection is drawing vacuum so I'm assuming that one will go to the wiper motor. I'm thinking that the original vacuum line (from the intake manifold) probably goes into the other connection on the pump in order to offer a little boost. That line from the intake manifold to the pump would also have to Tee off to the vacuum advance on the distributor. Or should the vacuum line from the intake go to the distributor first, then to the fuel pump? I'll appreciate any help on this. Thanks.--Don

[jclary]

Well...I have not had one of those double action fuel pumps on a vehicle since the 1960's. But, unless something has changed...you don't want to hook any vacuum lines from the fuel pump to the distributor. That distributor vacuum line should be independent of the fuel pump line and run only from its original position at the base of the carburetor to the distributor diaphragm.

One of those little tubes on the fuel pump is probably only a "vent" tube and the other runs only to the wiper motor. The manifold wiper vacuum fitting should be removed and plugged.

[dstude]

Thanks John, and no I certainly wouldn't run the vacuum line from the pump to the distributor. What is concerning me is that since both openings on the vacuum diaphragm housing are threaded it seems that there must have been some intention of a line going into both openings. Perhaps the second opening is simply a vent as you mentioned, but wouldn't there be some kind of a check valve or filter to keep road/engine dirt and grease from getting into that section of the pump. Maybe just a line that goes to an area of the engine compartment where there would be less chance of dirt getting in. As I said, this is my first experience with this type of pump.

Your vehicles look very nice, by the way.--Don

[jclary]

Well...with me, you're dealing with decades old info here, and memory is a challenge. However, if you think about it, once the vacuum line is hooked up to the fuel pump correctly...the air intake for the vacuum pump is actually at the wiper motor. That air flows from the wiper motor down through the tube to the fuel pump. The other opening in the pump is the exhaust. Therefore, at that point, nothing should be going "into" that opening since air is exhausting "out." If you want to make it neat, simply add a tube fitting with a small tube bent downward. That could be done with a flare tube fitting and a very small length of copper tube. (Probably a little overkill and not really necessary)

[brian6373]

Two things I think you might do. On the vent side of the vacuum pump just put a hose on it and put one of those plastic fuel filters on the other end to keep out the dust and stuff. The other thing is see if you can find a vacuum canister off an old Ford at the wrecking yard, I believe they had a built-in check valve, and run it in-line from your pump to the wiper motor. That way you still have plenty of vacuum at low RPMs. I did this on my 48 Chevy two ton truck, and it worked great.

[56pres]

Dust use is right. It goes to the intake manifold.

[dstude]

That's pretty much the way I ended up doing it, with about a 3" length of tubing coming off the exhaust port of the vacuum pump. I was just worried that there should be something more and I was missing it. One of the other club members mentioned a Ford vacuum canister that sounds intriguing; it apparently will maintain the vacuum charge that the pump has built so the wipers will operate at low engine speeds. Thanks again for your input.--Don

[dstude]

The Ford vacuum canister sounds like a great idea. What era (years, models) Fords will I be looking for and what is the basic size and shape of the canister so I'll know it when I see it? And where did Ford generally place them in the engine compartments? Thanks for the good tip.--Don

[brian6373]

Back in the 70's and 80's all the full size Fords, Mercs, and Lincons had vacuum for all the heater/ac doors and sometimes other acc. like headlight doors. These took a lot of vacuum. Depending on the model the vacuum cans were of various sizes and locations under the hood. Just follow the hose that comes out of the firewall back to the source. 25 years ago when I did this there were lots of those cars in wrecking yards. As I remember I got mine off a mid-70's LTD. There may be newer more plentiful cars out there in wrecking yards that you can scavenge a canister from. Maybe someone else here on the forum knows what newer cars came equipped with a vacuum can.

[dstude]

Thanks Brian.