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1928 chevrolet vacuum check valve


Guest bobgould

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Guest bobgould

I am looking for the check valve that is located on the middle top of the intake manifold, it screws in the manifold where the vacuum line to the vacuum tank is connected, can anyone help?

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  • 1 month later...

I think the thing you are looking for does not exist. There should not be any check valve there. The connection is a 3/16" flare fitting that connects to the vacuum type fuel pump on the fire wall, and the vacuum windshield wiper. If there was a check valve there neither of those items would work. The only check valve installed in this system is in the vacuum fuel pump and is indirectly controlled by the float. When the float reaches its overcenter toggle point it closes off vacuum and allows the gas to gravity feed down to the carburetor float bowl. When the float in the fuel tank lowers it allows vacuum to again draw gas from the gas tank. A small restrictor is installed in the top of the vacuum tank that is determined by the size of your engine. If you have a large engine then the size of the orefice can be somewhat larger. If you have a small engine then the size of the orefice should be somewhat smaller so the engine wont bog down as bad when the float is not calling for gas(vents to atmoshere at that point). There is access to technical advisors at the VCCA website, and a fellow near my house rebuilds those tanks as a side business. You should buy a 28 Chev owners manual from the Filling Station, they aren't that much money and can answer a lot of your questions.

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Guest bobgould

I am quite familiar with the workings of a vacuum tank, if you would look in the chevrolet repair manual on page 180 you then might understand a little more about how the system works. this book is also available from the Filling Station.

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That was supposed to be a condensed version since you were not getting any responses to your post. I have one 27 and four 28 engines out in the shop and there quite a few more laying around in this area, good luck on your search.

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Guest bobgould

I found a tank and it is the smaller one that will work,it is supposed to have a vacuum check valve to help it keep vacuum on hills or high demand,The truck now runs fine.

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