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AR Samba Member
Joined: September 10, 2025 Posts: 24 Location: Southern California
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Posted: Tue Dec 16, 2025 7:32 am Post subject: Gas Drip at Mounting Flange on 30/31 Solex |
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1970 Bug with a rebuilt 30/31 done by other.
I just installed it as the final part to getting her back on the road. Everything went well and drove well. But I noticed that the mounting gasket(s) were wet with gas which led to a small drip coming off the mounting studs.(see picture)
There are 2 gaskets that are installed because of the emissions control bracket.
I do not know if that is correct or not and may have nothing to do with the gas issue.
Do I have a float problem, a gasket problem or something else?
Thanks
AR
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messenger123 Samba Member
Joined: July 19, 2025 Posts: 49 Location: IA
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Posted: Tue Dec 16, 2025 7:39 am Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| Check the throttle shaft to see if that's the source of the leak. |
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AR Samba Member
Joined: September 10, 2025 Posts: 24 Location: Southern California
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Posted: Tue Dec 16, 2025 8:42 am Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| No leaks from the throttle shaft |
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messenger123 Samba Member
Joined: July 19, 2025 Posts: 49 Location: IA
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Posted: Tue Dec 16, 2025 8:46 am Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| AR wrote: |
| No leaks from the throttle shaft |
Pull the air filter and look down the carb throat with a flashlight and see if you can see anything leaking. |
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Cusser Samba Member

Joined: October 02, 2006 Posts: 33479 Location: Hot Arizona
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Posted: Tue Dec 16, 2025 12:08 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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1970 VW is exempt from California emissions testing. If mine, I'd remove that emissions control bracket and the throttle positioner part. _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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messenger123 Samba Member
Joined: July 19, 2025 Posts: 49 Location: IA
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Posted: Tue Dec 16, 2025 12:44 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| If you don't find any internal leaks, pull the carb and check both mating surfaces with a straight edge; they both need to be flat. |
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Bobs67vwagen Samba Member
Joined: March 27, 2005 Posts: 938 Location: Eastern north carolina
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Posted: Tue Dec 16, 2025 3:43 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| If the carb float bowl is overfilling it will leak down there. 2 probable causes are faulty float shutoff valve in top half of carb, they get gummed up and stick, and or excessive fuel pump pressure. |
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my3bugs Samba Member
Joined: June 18, 2003 Posts: 956 Location: Moreno Valley
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Posted: Tue Dec 16, 2025 3:51 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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i had a similar looking drip/leak there so i snugged that nut some . a while later i went for a 2 hour drive there n back n see the same thing , so i snugged that nut again thinking it was somehow coming loose . it wasent exactly running right either as it was sucking air in right there making it run lean .
it wasent coming loose , i was pulling the stud out of the carb . at first i added new threads to the carb n JB welded the stud in and it held long enough till i found another carb to rebuild .... may not be your problem . but it fixed mine issue .
have you tried to snugg the carb mounting bolts ?
Last edited by my3bugs on Tue Dec 16, 2025 3:58 pm; edited 1 time in total |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 36358 Location: Conejo Valley, CA
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Posted: Tue Dec 16, 2025 3:57 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| messenger123 wrote: |
| If you don't find any internal leaks, pull the carb and check both mating surfaces with a straight edge; they both need to be flat. |
I would do this and ditch the throttle positioner gizmo and plate. It's just more possibilities for leaks like you have. _________________ Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback |
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Cusser Samba Member

Joined: October 02, 2006 Posts: 33479 Location: Hot Arizona
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Posted: Tue Dec 16, 2025 5:56 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| my3bugs wrote: |
i had a similar looking drip/leak there so i snugged that nut some . a while later i went for a 2 hour drive there n back n see the same thing , so i snugged that nut again thinking it was somehow coming loose .
it wasent coming loose , i was pulling the stud out of the carb . |
I had this happen like 40-45 years ago; I used a larger SAE stud and nut (drilled the hole in the manifold a tad). _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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gt1953 Samba Member

Joined: May 08, 2002 Posts: 13959 Location: White Mountains Arizona
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Posted: Tue Dec 16, 2025 8:24 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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suggets you add this to the fle pump it keeps that pin in and fule pumping
_________________ Volkswagen: We tune what we drive.
Numbers Matching VW's are getting harder to find. Source out the most Stock vehicle and keep that way. You will be glad you did.
72 type 1
72 Squareback
({59 Euro bug, 62, 63, 67, 68, 69, 73 type ones 68 & 69 type two, 68 Ghia all sold}) |
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AR Samba Member
Joined: September 10, 2025 Posts: 24 Location: Southern California
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Posted: Fri Dec 19, 2025 10:19 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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Thanks everyone for your comments. I ended up replacing the mounting gaskets and it stop the gas leak. Having the emission control bracket sandwiched between two gaskets does lend to a leak problem.
I am considering removing the emissions like it was suggested to reduce problems down the line. I guess I was trying to keep everything period correct. |
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scrivyscriv Samba Electrician

Joined: October 04, 2011 Posts: 3378 Location: Memphis
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Posted: Sat Dec 20, 2025 10:53 pm Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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leaking gaskets there will show a symptom and not a cause. The carburetor shouldn't leak or drip, or otherwise discharge fuel after shutdown. Sometimes they do.. but they're not meant to. Float too high can cause it, or fuel pump PSI too high - or even the often-diagnosed, but usually not the problem, vapor lock related heat forcing fuel past the needle. _________________ Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help. |
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Bobs67vwagen Samba Member
Joined: March 27, 2005 Posts: 938 Location: Eastern north carolina
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Posted: Sun Dec 21, 2025 5:09 am Post subject: Re: Gas Drip at Mounting Flange on 30/31 Solex |
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| As Robert said above keep an eye on how it's running as there should not be late amounts of liquid gas down there. As said before it could be a float or fuel pressure problem. |
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