Sending Unit Leak

[volwing]

1973 SB replaced sending unit a while back. Notice gas smell after a fill up andl in the car. Saw where gas leaked from the sending unit where it is twisted into the tank. Is a there a sealant that can be applied to the outside rim of the sending unit/tank connection that will effectively stop the leak?

[ps2375]

Is there a rubber gasket between the tank and sending unit? Did you use a new one?

[volwing]

Yes new unit new gasket(O ring)

[BUGGED11111]

I've never seen that leak with a new O-ring. Must be an issue with the lip of the tank connection (bent/cracked) or the sender is flakey (Chinese?).

I would first see if it's possible to fix the reason it's leaking. Failing that try a custom gasket, something a little thicker than the o-ring. Not too thick or stiff or you'll have a problem screwing the sender on. You can get the material at most auto parts places. Obviously it needs to be gas resistant material. Gooping it up with sealant would be my last option

[volwing]

The O ring was a very tight fit. Don't think a larger one would fit. Possible the seal was bad as it was difficult to install. May have twisted it or squeezed it while tightening it. May loosen it and retighten.

[TheAmazingDave]

[Cusser]

It was decades ago on my '71 Super, but I do remember the sender/o-ring being a bitch to install.
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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

[Tim Donahoe]

I squirt (rub) a little WD40 on the lip of the tank where it contacts the "O" ring, then press and turn the sender to lock into place.

If you don't lube it a little, the "O" ring has a tendency to twist up.

Also, make sure the seal is seated well on the sender.

Tim

[irun5k]

I just finished overhauling my gas tank this weekend. For some reason PO had installed new sending unit and new gasket BUT also went absolutely nuts with some kind of silicone caulk between the gasket and the tank. I pulled huge globs of it out of the tank. Seems like it reacted with the fuel and got even bigger. Plus they had removed the filter sock meaning even the smallest glob would block the outlet nipple.

Anyway I can't imagine why on earth they did this. Seems too stupid to be something to just do for the hell of it. Maybe they had a leak before too even using the new gasket? Tank is newer, Brazillian, but looks like everything lines up properly.

Based on my bad experience I would strongly advise not using a sealant of any type, some of it could get in the tank even if you're careful. Try some of the other tricks here first and be sure to tighten the screws a little at a time vs. tightening one all the way and moving to the next one.

edit looks like SB unit is different than standard, so ignore my comment about screws.

[Cusser]

RTV is NOT resistant to gasoline !!!
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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