Leaking Carburetor

[Zylinderkopf]

this is the third carburetor developing a slow leak at the bolt on the bottom of the bowl (access to main jet). Anyone have any thoughts on a fix? I have an aluminum washer on it - is that part of the problem?

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1963 Beetle
1966 Beetle 1300
1970 Karmann Ghia Coupe
1971 Super Beetle
1974 Thing


"A lot of people never use their initiative because no one told them to."

[Eric&Barb]

[mukluk]

Remove the float bowl plug, clean and dry all mating surfaces, then apply some gasket sealant to both sides of the float bowl plug seal and reinstall. Permatex aviation, high tack, super 300, or even gasket shellac compound will all do the trick -- don't use RTV.
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1960 Ragtop w/Semaphores "Inga"

[Cusser]

[my59]

Our local hardware store stocks red fiber washers back in the nuts and bolt drawer section somewhere....
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my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget.

[zerotofifty]

I dont think the aluminum washer is correct here. it wont be soft enough to seal given how little force you can apply on the bolt without stripping the threads. fiber washer can be used here. The carb body is just to delicate to allow high enough torque on that bolt to assure sealing with an aluminum washer.

use of sealer is risky, as sealer residues may get into the carb, into the fuel, and then clog the jets. Use a fiber washer for trouble free service.

[mukluk]

[sctbrd]

Fiber gaskets is your best bet. Originals have lasted 40+ years. With no leakage. Or sealant.

[branston]

Most the carburetor repair kits come with the fiber washer, there's an example here:
https://www.thesamba.com/vw/classifieds/detail.php?id=2699178

[EverettB]

Since no one has said it yet, I think an aluminum washer would be 1-use only?

It would crush to fit and then as soon as the bolt moves for any reason, it could start leaking.
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[Zylinderkopf]

thank you everyone for your responses and advice. I will try cleaning up the mating surfaces and using a fiber washer instead of the aluminum washer. If the leak persists I will try some permatex aviation.

I will report back.
_________________
1963 Beetle
1966 Beetle 1300
1970 Karmann Ghia Coupe
1971 Super Beetle
1974 Thing


"A lot of people never use their initiative because no one told them to."

[zerotofifty]

note a solid aluminum washer is not a crush washer. a true crush washer has a hallow core, and they are indeed designed to be one use, but can on occasion be reused in a pinch. for this application a fiber washer is correct. do to the soft carb body, one may risk stripping the carb threads when attempting to crush a solid aluminum washer, unless it is extremely soft aluminum.

[mukluk]

Not all carb rebuild kits come with a fiber washer for the float bowl plug/main jet holder. Some come with copper, some come with aluminum.

Yes, the aluminum washers are meant to be single use, same as you'd expect for any metal sealing washer. Yes, they are a supposed to be a soft aluminum meant for such purpose, but IMO they do tend to be a little too hard. The same problem exists with many of the cheaper oil change gasket kits these days.

In my opinion and experience, using a little sealant on the washer before install helps to prevent any possible leakage due to hardness or minor deformation issues. It also allows one to reuse either the copper or aluminum washers several times which comes in handy if you don't have a stock of spare rebuild kits or a reliable parts source within a reasonable distance. Regarding the fiber washers, they tend to wick fuel over time if left untreated prior to install -- like most other paper/fiber gaskets, they benefit from a coating of gasket shellac before use.

Yes, the carb body is made out of a soft alloy, but then again the bowl plug/main jet holder often is a softer metal as well. Yes, if you're a gorilla about tightening things you can strip the threads out easily. Use a little sealant on the washer and you won't have to tighten it so much.
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1960 Ragtop w/Semaphores "Inga"