How I replaced my rusted, leaky fuel outlet nipples. (FI Tank)

[vwwestyman]

The outlet nipples on the tank in my '78 were pretty rusty and crusty. In the past I'd been able to get them to seal by smearing a layer of some kind of fuel tank repair epoxy on them. But last fall when I was doing some other work under the tank, I disturbed them enough that it must have cracked a little bit or something, and I could never quite get the slow drip fixed.

(I considered this simply an annoyance in this particular Bus since the tank is now used for diesel fuel.)

Anyway, since I had the motor out, I set about a much more permanent repair.

I originally thought about welding on some new tubing, but came up with something I like better! I went with screw-in fuel fittings from the FLAPS. Ultimately, this seemed a little easier than welding thin tube to think fuel tank material, and has the very nice benefit of being able to install the tank without the nipples in the way, so you've now got a couple more inches clearance.

First, a pic giving an idea of what my nipples were like. I cut one to help me find tubing that fit similarly prior to coming up with the ultimate solution. But it gives you an idea how bad they were.

Before going any further, I'll remind the reader that I was working on a tank that was used for diesel in the past several years, and that diesel is not really explosive, especially when compared to gasoline. I was satisfied with a good rinse with hot water prior to proceeding, you may choose to clean your tank further. (I'd probably simply do a good soaking with soap and hot water a couple times, but it is up to you to determine how you make sure you don't blow yourself up.)

I chopped both of the old fittings all the way off, and ground away the remaining rust around the tank area and also the old brazing or whatever was used to hold the old nipples to the tank.

Next you can see the package showing the new nipples I picked up from the FLAPS, along with two nuts that they screwed into. Watch out, many of these nipples use pipe thread. I was happy to find some with standard threads, because that allowed me to screw the nipples in easily, without having to cut pipe thread. I did consider welding a plate to the tank and cutting pipe threads in the plate (the tank itself would be too thin for this) but ultimately am happier with this solution. The only slight disappointment was that the threads are SAE rather than metric. Not really a big deal though.

Once the area was cleaned up, I welded the nuts on,with the nuts centered over the outlet holes. In retrospect, I could have made the outlet holes a little off-centered and bought myself a little more room for the welder but no big deal. I was struggling with wire-feed issues, and also some of the tank metal was extremely thin after grinding away rust. So the welds aren't that pretty because the wire wasn't feeding really well, and I was also having to close up holes. Please pardon the uglyness of the welds!

I did still have some of that tank seal epoxy, so I covered everything in a thin layer just to make sure there wasn't still a pin-hole somewhere.

Coat of primer and paint:

What the nipples look like installed:

I removed the nipples to install and strap in the tank. As I said, it was quite a little bit easier to maneuver in position because I didn't have those old outlets catching on anything.

I used some Permatex Fuel Resistant Gasket Dressing and Flange Sealant to seal up the threads as I installed the nipples from below. And with that, no more drips!

_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[lil-jinx]

Fine job,the brazing plays hell with welding,and it is near impossible to remove it all without taking away a lot of metal.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes.

[telford dorr]

Or you could have just brazed the nuts to the tank bottom. No ugly weld problems, smooth leak-free finish, no epoxy. I use brazing to attach sheet metal strengthening doublers to damaged engine sheet metal where bolts hold it to the engine. Works great. Just saying...
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[lil-jinx]

Brazing seems to be a dying art,
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes.

[vwwestyman]

Yes, I suppose brazing would have been a little easier if I had the equipment. However, I have a MIG welder and only a propane torch. I understand brazing isn't technically impossible with a propane torch, but is somewhat difficult to get the materials hot enough to flow the filler.

Perhaps I could have spot-welded the nuts and used solder to seal up the joints. Seems like I was able to get a little bit of solder to flow into a very small leak in the nipples that were on the tank I installed in my '73 when I changed to fuel injection. But after grinding away the rust, I may have still had some pin holes that wouldn't have been seen/filled when doing that.

I suppose the principle here is that no matter how you attach the nuts, changing the rust-prone tubes to nuts and screw-in nipples is a pretty viable solution.

As I type this, one could also consider changing to AN type fittings, or something else and potentially put in things like fuel shut offs and all sorts of fancy stuff.

My solution was readily available at the FLAPS that morning.
_________________
Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Wildthings]

If I ever have to go down this road, I think I will just braze in the top of some other tank that uses a submersible pump and thus eliminate the bottom outlet and return all together. Might as well modernize a bit as I go forward. This would also lessen the likely hood of the tank emptying itself into the flames in the case of an engine fire.

[Mispeld]

Stupid question - What brazing rods would you use on sheetmetal? I use 15% silver on copper for HVAC. Comes out like boogers made of mixed peanut butter and superglue on sheetmetal.

Speaking of HVAC, I would pressure test the tank with about 3 psi before putting everything back together.
_________________
Tom
1977 Westy. 2.0 Fuel Injected.

[telford dorr]

I use the generic flux-coated brazing rods they sell at the welding store.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[Wildthings]