Model B 4 cyl Zentith Carb

29Cabriolet

29Cabriolet

Senior Member
My car is a 29 Cabriolet but I'm visiting this site because the engine in my car is a 32 Model B. I am in the process of rebuilding a carb and have a question regarding the housing for the GAV needle valve and seat. How is the housing and seat removed from the lower body? Assuming it is threaded, I tried to remove it with pliers but it won't budge. It does not have a hex as on earlier models. I spoke to the rebuilder at Bratton's who said he'd never seen one like that. I was hoping someone on this forum can offer some advice. Here's a couple pictures.

Many thanks for all advice or suggestions!

29Cabriolet
a.k.a. Stan
 

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The gav housing is pressed into the base. To remove them I made a little slide hammer that screws in where the needle goes. It is an oddball thread pitch, 1/4-24 tpi I think. A couple raps and out it comes. Don't lose the little spring. And washer under the housing, it keeps the needle from self adjusting.
 
Mark in MT said:
The gav housing is pressed into the base. To remove them I made a little slide hammer that screws in where the needle goes. It is an oddball thread pitch, 1/4-24 tpi I think. A couple raps and out it comes. Don't lose the little spring. And washer under the housing, it keeps the needle from self adjusting.
Click to expand...

Thanks for the reply! I guessed it wasn't threaded since it wouldn't budge by twisting. And you've confirmed it!

I'll give it a try.
 
Bratton's carburetor rebuilder shouldn't be allowed to take phone calls given that his lack of knowledge is a liability to their business. All, not just a few, oval bowl '32-'34 Zenith carburetors are constructed in this manner.
 
Unless there is some compelling reason to remove it, i.e., damaged threads or accumulated crud, I would leave it alone. It is very easy to damage the Model B GAV housing - some are hard to remove.
 
I second ursus' counsel. The key word being "compelling". If it is strictly for cleaning and painting purposes, leave it be.
 
I just replaced mine with this kit provided by Renner's Corner. Mine became loose so I had to replace it. Spoke with Dave Renner who advised on the procedure to follow. The photo shows the order of the internal components. The housing for the GAV needle on the model B is pressed down, no threads. Dave suggested to put a fine coat of a threadlocker like green 3M on the GAV housing before inserting into place. I used blue Permatex which I had available and then pushed into place with gentle blows with a piece of wood. It will likely get deformed when removing with a plier but since it is not threaded I think that will be the only way to get it out.
 

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I have two Model B's and have never used parts labeled "C" and "D" in the photo above and I don't see them on the Ford parts book diagram. What is their purpose? Am I reading it right that they go between the seat and the needle valve?
 
Those parts do go between the seat and the end of the GAV housing. They perform the same function as the extended brass "fingers" and ring on the Model A GAV, which is to maintain tension on the needle so that it stays in position.
 
One more question, I am still confused. In my post above I meant to refer to parts D and E in the picture. Were these used originally (I don't see them in the parts books or catalogs) or are they an upgrade?? It looks like they go inside the GAV tube below the needle is that right? In the layout it looks like they go in the carb housing before the tube which seems strange to me. Thanks for your help. Jim
 
I had assumed the intent of your question and answered it in post #13. Parts D and E are installed first inside the lower carb body and the tube is installed after them . Study a picture of the Model A GAV housing tube and you will see that there is an internal extension that performs the same function as the spring and washer in the Model B carb.
 
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