I opened the hood on my '59 today and started it up, and LO! It HAS the vacuum-wiper style fuel pump!! It's made by AC, and although it looks new, it also looks like there's a silver-Permatex-type repair made to a gasket surface ABOVE the output to the carb. Need to look at that.

But I need education on the (2) vacuum/pressure ports on the top cap:

(1) is ported to the intake manifold, under the carb base. What the heck is that for?

The other one (labeled "wiper") is open, no tube going anywhere. The vacuum-leak noise I mentioned in an earlier post is coming from this port, and it is in fact "sucking" as I press my finger over it.

Also, the engine speed increases when I block it with my finger, which would indicate a REAL-live intake vacuum leak, but how is the wiper port in any way connected to the intake manifold?

This wiper port has no visible threads on the ID, so how is a vacuum line supposed to be attached to it?

Last: If I were to attach a vacuum line somehow to this port, do I run it straight to the wiper box on the center/upper firewall?

 

Some wiper systems were vacuum, some were mechanical/electrical. The vacuum line came off the fuel pump. Mine had a fuel pump like that with the wiper port blocked since the wipers were electrical. Are your wipers working?

 

I have no idea if they work, they were unhooked when I got the truck. That is, the vacuum port on the top of the pump was/is not hooked up to the wipers.

 

Strangely enough, the 1960 shop manual does not say how this is connected, at least that I was able to find. It does refer to the unit on top of the fuel pump as a "vacuum booster". Mine has a steel line running from the manifold to the vicinity of the fuel pump, a rubber line is then run from the steel line directly to the wiper motor; both ports on the booster pump are open. The fuel pump part of my mechanical fuel pump has also been bypassed with an electric fuel pump, so I don't know what's wrong with it. It looks fairly new.

Based on this, I believe that the steel line at one time connected to one port of the booster pump and the other port went to the wiper motor. My guess is that at low RPMs manifold vacuum runs the wipers. As the RPMs go up and manifold vacuum drops, the booster provides more and more vacuum to keep the wipers running.

I'm not sure if you're talking about the port on the booster pump (part of the fuel pump) or on the wiper motor. My booster pump has two 1/4" OD tubes sticking up out of the top. My wiper motor apparently has a fitting sticking out the passenger's side, as the rubber hose I mentioned is attached with a hose clamp. Either way, perhaps the fitting was just pressed in and has been pulled out? If that turns out to be the case, you have several options:

First, see if a length of 1/4" tubing will fit in the opening. If it's not too loose, you can probably glue it in there with RTV or hot glue. Since its a vacuum system, the pressure will help hold the fitting in place.

Second, try to find a plastic barbed fitting that will fit, proceed as above.

Third, you could have a machine shop make you a new press-in fitting. I would pick up a 1/4" brass male to male barbed fitting at the hardware store and have the shop machine off the barbs on one end and turn in down to the ID of the hole in your wiper motor or booster pump. This is a real quick job for anyone with a lathe, so if the guy want's too much money to do it, go to another shop. You will need to know the ID of the opening. You could use the shanks of drill bits to find the one that is a nice snug fit. Better yet, bring the truck with you and get the machinist to measure it. Once you get the new fitting, hold it in place with some high strength Locktite or RTV.

Let me know how you come out and what works, as I am probably facing this problem too.

Cal

 

Cal 401:

Do your wipers work hooked up like that?

I think your analysis is valid: Vacuum supplied from the manifold (THAT'S what my line from the manifold to the booster is for!) drops as the throttle opens, hence the need for the booster. That's ALSO why my engine speeds up when I put my finger over the wiper port on the pump, it's a major vacuum leak!!

I can't imagine why the pump was supplied without a tube sticking out of the wiper port, but I'll just find a close-fitting brass or plastic tube to put in and rtv or JB-weld it in. Mystery solved.

Thanks!