Sealing a Plastic Fuel Tank

jymmiejamz

Founding Member
Callsign: KN4JHI
I'm going to be installing a Britpart auxiliary fuel tank in my 110 once I burn through this full tank of diesel I have. The tank looks to be the same as the Mantec tank they used to make. It is meant to be installed with a metal 110 tank that has a drain plug. The intended installation would utilise the drain plug for the balance pipe on the bottom of the tanks. This is a pretty bad design since if you were to hit it on something you could potentially drain both tanks onto the ground. I don't have this option anyway, as I have a plastic tank. Here is an image from the Mantec instructions (none provided with the Britpart tank).

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In my D90, I have a Safari Equip auxiliary fuel tank which comes with a fitting that you fish through the filler neck on a piano wire to a small hole that you drill in the side of the tank. I want to do this with the 110 tank. Here's a pic from the web to give you an idea of how it is in a D90.
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I can't really remember exactly what the fitting actually is in the D90, but I've ordered a bulkhead barb from Amazon that I am going to use. The fitting looks like this.
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My question is what should I use to seal this fitting on the plastic tank? I don't recall there being any kind of sealing washers on the Safari Equip setup and it doesn't leak.
 

acheck

Well-known member
that is an interesting looking fitting. i am curious how the male and female halves seal to each other. most bulkhead style fittings are designed much differently with 3 total pieces, not two.
 

jymmiejamz

Founding Member
Callsign: KN4JHI
I'm not sure if this is clear to you from the picture, but that is just a nut that is threaded on. The main difference from the Safari Equip fitting and the one I posted is that the Safari Equip one is just flat on one side and a hose barb on the other with a hole in the middle for fuel to flow through.
 

jymmiejamz

Founding Member
Callsign: KN4JHI
I like the AN fitting idea, but it needs to be a 5/16" hose barb on one side. I'm guessing that's readily available.

Do we think the plastic washers that are supplied with those fittings would be good for sealing? I could give those a try with the fitting I have one the way.
 

WreckITFrank

Technical Excellence Contributor
I like the AN fitting idea, but it needs to be a 5/16" hose barb on one side. I'm guessing that's readily available.

Do we think the plastic washers that are supplied with those fittings would be good for sealing? I could give those a try with the fitting I have one the way.

6 AN is about 5/16 I think. So maybe find that size. I would start the hole small and keep stepping it until it just fits. Not sure how thick the tank is, but should still seal with the washers. As Dave said you could seal it up if needed after you test it.
 

jymmiejamz

Founding Member
Callsign: KN4JHI
This is the fitting I wish I had. This is the one that comes with the D90 Safari Equip tank.







Since I have no idea where to buy such a thing, I'm looking for some sealing washers like these read ones that would be suitable for plastic and diesel fuel.
 

jymmiejamz

Founding Member
Callsign: KN4JHI
That could work. I would need to remove that screen because you use a piano wire to fish it through the filler neck into the tank.
 

JimC

Super Moderator
Staff member
When I swapped out my plastic tank for a long-range metal one, I discovered a hole had been plugged with a self tapping screw and a rubber washer. It worked great and never leaked, I’m optimistic for for your proposed solution.
 

rlynch356

Well-known member
when you install the aux tank, you only want to do it once, its a pita to get everything lined up and in place (I have a ZA one on my 110 which is similar to the Mantec one).. the aux fuel line through the drain hole is pretty exposed and if I ever drop the tank again completely I'll go the same route as you with the fitting in the side lf the tank. (and use a new tank too)
 

jymmiejamz

Founding Member
Callsign: KN4JHI
Yeah using the tank drain on a metal tank makes for an easier install, but seems like a bad design.
 

rlynch356

Well-known member
I agree, but then again mine did over 100k off road in Africa and thats the way it was done at blackheath.. I do now have a X-Eng sway bar fitted which should stop and rocks at least from hitting it
 

jymmiejamz

Founding Member
Callsign: KN4JHI
Circling back on this… I went to install a water tank in the left rear of my 110 and realized my tub has a step down that not all 110s have. I just dropped my water tank off to be modified to fit my tub. Im also going to need to do the same with my aux fuel tank to install it. I just ordered a -6AN bulkhead fitting for the balance pipe. It includes two Teflon washers. Do you guys think I should go with these Teflon washers or get some dowty seals?
 

jymmiejamz

Founding Member
Callsign: KN4JHI
I can appreciate that, but was thinking rubber is softer and would seal better against the plastic tank.
 
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