MTFCA Forum

I'm helping a friend with his Stewart vacuum fuel pump. I cant find the right size fitting for the fuel inlet. Anything I try is either to big or to small. All the other holes are 1/8 and 3/8. But the fuel port is an odd size. Anyone know what size it is and where I can find it? Thank you.

These photos might help, they have the thread size for fittings. Don't know where you obtain any.

Thank you.

FWIW, screwing fittings into potmetal fixtures like the vacuum tank top is fraught. On my Tarrant special T tourer, I often have to prime the tank if the car sits for a month or two. Into the port that takes the steel plug sealing that hole, I screwed a brass adaptor, sealed with permatex. The steel plug is then screwed into the brass adaptor. This means that the potmetal cover is left untouched, one wrench holding the adaptor steady and the other tightening the plug.

Allan from down under.

You can try Bob’s Automobilia in California.

Also, there’s a place in Australia that sells parts for these. I can’t remember the name of that one.

They actually used a couple different sizes on tanks intended for different automobiles. So, it is possible that your tank may be different. I know that Buick for a few years used a size for the fuel inlet that was different than most Stewart vacuum tanks. It required a special donut shaped end on the fuel line that was usually soldered onto the fuel line. Then a special hollowed out "compression bolt" that went through the "donut" and transferred the fuel to inside the vacuum tank. Why they were that way? I have no idea. But it caused me problems over forty years ago when trying to fit a vacuum tank to another car and it turned out the tank I had was from a Buick.
I have over the past years run into a couple other cars that used that odd size fitting.
The non-Buick size vacuum tank I ended up using on that car years ago, I found a common plumbing bushing fitting (adapts one pipe size to another) that fit the tank, and then a common other elbow fitting that worked. Whatever size they were? It all worked fine for the several years I had and drove that car.
I can't get to much of the little bit of vacuum tank stuff I still have right now to measure it. So don't have actual sizes to give you. If you have a good thread gauge set, that could give you a good starting point.

If you end up needing a new top for it I know that Meyers early dodge has tops for at least the Dodge size and a fair deal of parts for them as well. They’ve been pretty helpful to me and if it’s not the right size they may know where to get a different sized top.

The Dodge ones with which I have limited experience are a size bigger than the one on my Tarrant tourer. The Tarrant has the fuel tank suspended under the spare tyre carrier at the rear of the car. Hence the need for the vacuum tank.

On a one-of-kind Duncan and Fraser built tourer, they lowered the front seat, so that meant a special hand made square fuel tank, with a drop section between the frame rails to maintain capacity. That also required a vacuum tank. When I restored it, the owner had the tank rebuilt off site, and it came with the fittings already installed on the top. The plumbing lines were hooked up as oriented, but there is no way the car would run. After much tinkering, it was finally realised that two of the pipes were hooked up the wrong way round. The orientation of the top fitting had led us astray!

Allan from down under.