Fuel Sending Unit/Top Leak

[JKowal1980]

Hello all,
Improvements are going well on our 1972 Standard Beetle. We do have a slight fuel leak at the top of the tank, especially after a fill up. I don't think it's a safety issue yet, but the smell of gas is a concern for my wife (not to mention the miniscule waste of fuel). I presume there is a simple gasket within the fuel sending unit that would be a straight-forward fix. Am I missing something?
Thanks for any input!
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[67rustavenger]

Pretty simple gasket replacement.
https://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=113919133
When you change the gasket. Be careful when tightening the fasteners.
You want the sender to get sealed. If you over tighten the fasteners, you can crack or break the sender.
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GFY's Xevin and VW_Jimbo!

[baldessariclan]

In addition to the gasket, don't forget the plastic/nylon sealing washers under the sending unit's mounting screw heads -- like these: https://www.bugcity.com/shop/shop.lasso?pquery=n138021. Note that the washer under one of the screw heads is usually a soft copper washer, used for both sealing and to provide a grounding path for the sending unit to function properly.
_________________
1971 Standard Beetle — fairly stock / driver

baldessariclan -- often in error, never in doubt...

[KTPhil]

It can also be a failed rubber sealing sleeve in the thick hose from the fender to the tank. Could even be an issue with the tank fume hoses.

[heimlich]

I made this. I had the seals made out of the same stuff they use here in Houston.

https://www.thesamba.com/vw/classifieds/detail.php?id=2630059

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[runamoc]

I used a liberal amount of gasket sealer to stop the leak. Then to make sure I had a good ground...

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Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
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Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
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[Cusser]

[runamoc]

[AlmostHeavenWV_VW]

Aftermarket seals didn't work for me.

https://www.thesamba.com/vw/forum/viewtopic.php?t=774134&highlight=
_________________
1973 Standard Beetle
1600DP AK case
Solex 34PICT3 Carb
Bosch DVDA 205AJ Distributor

[JKowal1980]

Thanks again for the insights. I think I'll replace the sending unit and gasket, as they are affordable enough. My gas gauge also will never go past 3/4, so I wonder if the float is compromised due to age?

Upon closer inspection, I definitely have a breathing issue. Some past owner has cut and capped the breather lines on BOTH sides of the gas tank. This is a 72 and I do not see any remnants of a charcoal can. So, it's MacGyver time. I assume I can run a replacement line up, around, and down to slow fuel vapors, then get it out of the body underneath. Does anyone have tips on what size of hose is best? How do I know where the exit penetration should go (not glaringly obvious)? How far beneath? How important is the driver's side compared to the one that is off of the fill port? If someone was willing to give a simple overview of how the whole system is intended to work, I would be happy to know more, too. Thanks!

[AlmostHeavenWV_VW]

[JKowal1980]

Lots of great photos and info. Thanks!

[BMFBMF]

Hi, looking at the insulated terminals, it looks as though you did not use the proper crimping tool, those terminals do not have a great reputation but they can work well if crimped properly, the proper tool squeezes the wire crimping part as well as the cable part, but to a different degree, in order to ensure strain relief.
The proper crimping tool bends and folds over the steel wings onto the wire end, whereas just squeezing them results in a very hit and miss crimp
_________________
-----Slava Ukraini-----
1971 Stock South African Beetle 1300 : My mom's european "Thin Chick" spec. Completely stock with torsion bar front, swingaxle rear, smooth hubs, single MC, 40 mm shoes, 31PICT3 carb and 5 bolt drums all round, currently Running a 1976 SF:AS engine with the original SF:AD engine overhauled in a box, waiting to go back in one day.

[runamoc]

[JKowal1980]

Hello all,
I was able to get an OE expansion tank for under the trunk lid from eBay. Depending on whom you ask, a 72 standard was never supposed to have one. There certainly is no trace of a bracket or connectors on mine. At any rate, I'd like to include it. Here are a few questions for those who know:
Can I make my own strap bracket to hold this to the sidewall? I have a rivet nut tool gun to do it right.
Is the intent to pad this with weatherstripping, etc., to prevent rattles and fatigue?
Is grounding of this metal tank of any importance?
Is there really an input side/output side? They look the same and I was just going to keep the numbers right side up.
Thank you!

[74 Thing]

The Thing has a strap with it welded to an inner trunk wall

https://www.thingparts.com/search.php?search_query=expansion&x=0&y=0

Maybe you can use that with a timesert.

There are lots of Thing parts in the classifieds where guys are parting out-maybe you can ask around if one of the straps is available for purchase.

Good luck

[runamoc]

[baldessariclan]

[JKowal1980]

I don't think it turned out half bad. For full disclosure, this system currently ends with the downturn going under the trunk.

I was disappointed that the new sending unit acts very much like the old one, showing only about 5/8 when the tank is known to be full. The previous installation had NO washer on one of the five screws; I presume that was on purpose for the ground path. I found out on the first fill-up that some sort of washer is non-negotiable, or gas will continue to leak. I will plan for some copper crush washers in the future, but in the meantime I put the fifth plastic washer on that came with my replacement sending unit. Oddly enough there is still a circuit being made. Has anyone had an issue with the fuel gauge in the dash itself? My next step is to clean off the gas tank to body clamps and see if it gets any better.

[heimlich]