Ultimate well nut repair

[Daybreak]

File under: You pays your money and you takes your chances.

Can't find my post on this topic from many months ago, but I'd bought TWO of these from Green Mountain Generators as spares (the update had already been done on my 802a, including the dremel cutout on the frame, but you never know) and was curious about whether they'd hold up to Diesel (#2, ULSD, stuff from local pump, what I use in the HMMWV and TQGs). Several other people mentioned problems with buying what they thought were diesel-proof wellnuts, soaking one in fuel for results.
So I plunked one of the two I had into a jar of Diesel fuel and let it sit for at least 6-8 months, maybe longer.
Take it for what it's worth, maybe nothing, but the numbers are different on the different wellnuts. I only noticed this today (while I had my reading glasses on).
Now, while swelling may or may not be a sign of breakdown, I SWEAR the fuel I poured into the jar was a LOT closer to clear - or at least a helle Lager Bier) and not imminent signs of kidney failure, or dunkel.
Does ANYONE have a source for honest-to-goodness N-BUNA rubber wellnuts that won't swell, leak, degenerate under exposure to diesel fuel?
Thanks.Norm

Howdy,
I do not know what they sold you. I had, and sold 40+ true military surplus A3816 nitrile rubber well nuts. You can go look at the thread with the pictures.

The infamous Well Nut info

 

[Light in the Dark]

So the question stands... if there are nitrile models available, and they were what was used OEM... why do these leak still? I understand the spec calls for nitrile, but this part seems to be a very common failure point on even the most upkept machine.

 

[Light in the Dark]

Howdy,
I do not know what they sold you. I had, and sold 40+ true military surplus A3816 nitrile rubber well nuts. You can go look at the thread with the pictures.

The infamous Well Nut info

And those shots you took do show the 4 dots at the inside tank end on the fitting, so I believe those are Parker nuts (they also say pat. pend. for the term Wellnut on them). Most manufacturers have little interest in discussing expired contract military specifications with Joe Schmoe off the street (ask me how I know).

 

[Daybreak]

So the question stands... if there are nitrile models available, and they were what was used OEM... why do these leak still? I understand the spec calls for nitrile, but this part seems to be a very common failure point on even the most upkept machine.

Howdy,

A lot depends on how they were installed. Was it installed to tight?, did it get hit from the side?, did the JP-8 eat it away? Did they always install a nitrile rubber well nut? Maybe from the start they did not. From the PS Mag 2012 article, it sounds like they might have used just rubber, and JP-8 ate them up. The new style, for fuel compatibility is Buna N (nitrile rubber).

If installed properly, and simply using #2 diesel, they should last without issues.

 

[Light in the Dark]

Being that they stopped producing the TQG in '12, when might they have phased in a 'new style'? Not sure we will ever know (and unless our resident DRS folks know/remember this detail), it might be an open ended question. I do hope those looking find the Nitrile at the end of the rainbow.

 

[Light in the Dark]

So FWIW, on the big auction site are currently what you are looking for. Search for 'fastcashmoneyman' and you will find them (actually SS user Suprman). $12.99/ea and rated for diesel according to the auction.

I still like the bulkhead fittings

 

[Hard Head]

Forget the wellnut guys. Put in a bulkhead fitting and never look back. It is so easy even I can do it. I no longer use wellnuts on anything. Not even water tanks. For $10 bucks more you have a permanent fix. Vitron will not dissolve in diesel. Save money on something that doesn't matter. No fuel, no generator!

Some facts:

Viton o-rings are an upgrade to the original neoprene seals on Corvair pushrod tubes that deteriorated under the high heat produced by the engine, allowing oil leakage.Viton tubing or Viton lined hoses are commonly recommended in automotive and other transportation fuel applications when high concentrations of biodiesel are required. Studies indicate that types B and F (FKM- GBL-S and FKM-GF-S) are more resistant to acidic biodiesel. (This is because biodiesel fuel is unstable and oxidising.)
Viton o-rings are an alternative to Buna-N seals in BMW's automobile engine variable timing units, known as VANOS. In the VANOS, the Buna-N o-rings deteriorate. The Viton fluorocarbon o-rings have similar functional characteristics to Buna-N, but with much higher temperature and chemical resistance characteristics.

 

[Light in the Dark]

I am with you HH.

 

[NormB]

Forget the wellnut guys. Put in a bulkhead fitting and never look back. It is so easy even I can do it. I no longer use wellnuts on anything. Not even water tanks. For $10 bucks more you have a permanent fix. Vitron will not dissolve in diesel. Save money on something that doesn't matter. No fuel, no generator!

Some facts:

Viton o-rings are an upgrade to the original neoprene seals on Corvair pushrod tubes that deteriorated under the high heat produced by the engine, allowing oil leakage.Viton tubing or Viton lined hoses are commonly recommended in automotive and other transportation fuel applications when high concentrations of biodiesel are required. Studies indicate that types B and F (FKM- GBL-S and FKM-GF-S) are more resistant to acidic biodiesel. (This is because biodiesel fuel is unstable and oxidising.)
Viton o-rings are an alternative to Buna-N seals in BMW's automobile engine variable timing units, known as VANOS. In the VANOS, the Buna-N o-rings deteriorate. The Viton fluorocarbon o-rings have similar functional characteristics to Buna-N, but with much higher temperature and chemical resistance characteristics.

I can spend the next hour, hour and a half, using the search function on this website for “bulkhead fitting” or ask directly:

What specific fitting do you recommend? Got pictures?

Thanks.

 

[Light in the Dark]

If you head back to the first page of this thread, you will see it.

 

[Zed254]

An excellent install presentation by Triton here: https://www.steelsoldiers.com/showthread.php?171091-Ultimate-well-nut-repair/page6

 

[NormB]

802a. I couldn't bring myself to fix junk with junk, not on my machine. Maybe a grass cutter.Nitrile or not those things are doomed. This even comes with a viton o-ring. Here is the permanent fix. $10.99 + S/H
You do need to remove the fuel filler so you can get your arm in the tank. I was going to fish it in with a small piece of cable but I decided I wanted the tank spic and span. Fishing it through would be tough but on a bet I could pull it off.
Here is what you need.
http://www.plastic-mart.com/product/10047/arlington-10897
And a 3/4 inch washer , perfect fit no modifications required.
View attachment 696717
It is a tight fit on the inside radius of the tank but it proved to be no problem. Enjoy

Looks awesome, but... chat's not working, I'll call.

 

[Light in the Dark]

Call them... that shipping figure is outrageous.

 

[Light in the Dark]

They are only a few ounces each, and you can fit 1 or 25 in the same size box they will ship in.

 

[Light in the Dark]

Here is the same part, a few bucks less: https://www.tank-depot.com/productdetails.aspx?part=A-10897

Think thats where I got mine. Call in and ask for better shipping rate here too. They dont even stock these things, they ship from Ace Roto-mold!

 

[rcamacho]

Great thread and write up. +1 MEP 802a with this leak.
Ordered a pair of bulkhead fittings today.


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[mijoe]

And a 3/4 inch washer , perfect fit no modifications required.

It is a tight fit on the inside radius of the tank but it proved to be no problem. Enjoy

I just wanted to reach out here and let you all know that I found a good washer to go on the outside... It is actually a bronze thrust bearing that my Ace Hardware has in stock in the misc metal parts aisle past the screws and such. The part number on the box was 58096-K, but the fellow couldn't ring it up at the counter, so he just rang it up as misc parts and charged me 15 cents each.

 

[Chrispyny]

Replaced my return well nut last week while on vaca. Thought i’d pop in just to mention it. I had done this fix for my feed on the low side over a year ago. Thought i torqued the new well nut well enough on the return on the top side well enough where i wouldn’t need to spend the roughly $20 on that.

Nope, i started to see a leak a couple months ago. I keep the tank topped off to the top of the fill neck. The return well nut let go and leaked the pint or so of diesel past it that the fill neck holds. Dang i was so pissed. So i bought a new fitting a month ago, some new stainless hardware and capture nuts which i have been meaning to fix and on vacation fixed everything.

I honestly have no clue how the military let go this poor engineering mistake. The bulkhead fitting is the perfect solution.

 

[rcamacho]

Replaced both drain and return wellnuts on 802A today. The return was easy to access and fish though with a wire. The drain was not feasible to tighten due to interference with the sheet metal. I had to completely remove the radiator and supporting structure to R&R the tank. This was a huge PITA.


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[Chrispyny]

I did my pick up with the tank mounted in the genset. I hogged out the aluminum at the nipple with a dremel. Didnt need to take it apart at all.
Wish i knew you were thinking of doing it the hard way, we could have given you tips for an easier job.