1957 Holley 4 barrel leak

[TbirdFan76]

After cleaning the carburetor while on the engine using carb cleaner and soft bristle toothbrush a leak occurred. It seems to be coming from the bottom of the front reservoir diaphram.

1. Is it possible to take the front bowl off the carburetor to inspect and repair the diaphram without removing the carburetor from the engine?
2. Alternatively Is there a way to remove the accelerator diaphram from the carburetor from the bowl? It would require a tool to remove the screws which are on the bottom diaphram which are not possible to remove with a standard screw driver?

All advise is welcome.

Engine is a 312 Y block with holley 4bbl carburetor. Per Barrett-Jackson Auction listing this is an original car with only cosmetic updates to the convertible top and interior.

Thanks.

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[Frankie the Fink]

If nobody else responds you could call Ron or Tim at Daytona Parts with your questions: https://daytonaparts.com/
They are based in Florida and I've had dozen of superb dealings with them, including tech questions.

 

[Tom Alpers]

Removing the carb on these cars is one of the easiest things to do. If it's been on there awhile you should use new gaskets to replace any that get disturbed which would include the two large ones for the manifold and the spacer that's under the carb. Since you have a leak which presumably you hope to fix, I would order a rebuild kit before starting to take things apart. It will have the gaskets for the front bowl and I would expect it to have a new diaphragm for the accelerator pump, the things that seem most likely to be leaking from your description. Get the list number off the front of the carb air horn to help in ordering the kit. That daytonaparts place should be able to get you the right kit.

 

[doug7740]

After cleaning the carburetor while on the engine using carb cleaner and soft bristle toothbrush a leak occurred. It seems to be coming from the bottom of the front reservoir diaphram.

1. Is it possible to take the front bowl off the carburetor to inspect and repair the diaphram without removing the carburetor from the engine?
2. Alternatively Is there a way to remove the accelerator diaphram from the carburetor from the bowl? It would require a tool to remove the screws which are on the bottom diaphram which are not possible to remove with a standard screw driver?

All advise is welcome.

Engine is a 312 Y block with holley 4bbl carburetor. Per Barrett-Jackson Auction listing this is an original car with only cosmetic updates to the convertible top and interior.

Thanks.

Yes, it is possible to remove the front bowl without removing the carburetor from the engine. Years ago, some Holley fuel-bowl screws had a slotted head that required using a flat-blade screwdriver. The common screws used today have a hex head, which require a 5/16-inch wrench. Crack each screw loose, and then continue to remove all four. Each fuel-bowl screw seals to the fuel bowl with a sealing washer. If the washer does not stay with the screw, it’s likely stuck onto the fuel bowl.





The gasket on the fuel bowl may cause the fuel bowl to stick. Do not jam a flat-blade screwdriver or chisel between the fuel bowl and metering block as this can gouge the mating edges. A light tap with a plastic hammer pops it loose.

The accelerator pump on the primary fuel bowl is secured with four 8-32 screws. Use a Phillip screw driver to remove the four screws securing the accelerator pump to the bottom of the fuel bowl.





At this point you will need a new fuel pump diaphragm and check valve, fuel bowl gasket, fuel bowl screw seals and fuel transfer tube seals. Since you are seeing fuel leaks from the gaskets and seals, if it were me I would remove the carburetor and perform a complete overhaul.

doug7740
1955 Thunderbird Blue

 

[Pink T-Bird]

In addition to the excellent explanation by @doug7740 make sure you get the viton version of the diaphragm. It holds up to the crappy alcohol laden fluid that passes for gasoline today. Most of these diaphragms I have seen were green not black.

 

[TbirdFan76]

Hmmm...yesterday I ordered a kit made by Holley. A shot from the kit of the diaphram is green. @Pink T-Bird,Is this the one you are saying is not good?

 

[Pink T-Bird]

Sorry I was not clear. This IS the green viton diaphragm. You are good to go. The non viton ones are all black.