Fuel tank breathers question

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itchyfeet
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Re: Fuel tank breathers question

Post by itchyfeet »

its easy to think you are an expert with a bit of googling and start modifying stuff but if you don't really understand fuel tank design best leave it alone imo.
I'm sure the design is there to cater for things you don't normally experience but you might one day.
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Re: Fuel tank breathers question

Post by crazyhorse »

Right then, Im going to do this.

Tank out. Some Bilt Hamber UB in the space, then get rid of the breather tanks.

What would you advise to blank off breather tanks pipe from tank??


I never fill the tank up to max, never have any money too
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Re: Fuel tank breathers question

Post by shepster »

I can only say what I've done on mine so you have to decide for yourself.

If you look at the photo for reference, the metal pipes that are part of the tank I capped off with plastic 'caps' and the ones across the top of the tank I simply 'plugged' the ends .

I also run on LPG so never fill the tank up as Petrol is only a backup.

Probably 5yrs ago now so I guess I would have found a problem by now.
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Re: Fuel tank breathers question

Post by MGP »

The breather tanks are also there for safety the same as the non return valve in the return hose on vans fitted with carbs that people remove "because they don't do anything". The breather tanks house the valves that close the tank off in the event that the van ends up on it's side or roof.
Before modifying any of the fuel system take a moment to think what's going to happen if you turn things up the wrong way.

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Re: Fuel tank breathers question

Post by chewbacca »

You see, I'm still not sure on this. I have a very limited experience of fuel tanks, but all the ones I've seen just have a breather pipe out the top. Car ends up on its roof, fuel comes out.
Where are the non-return valves in the breather tanks? That makes even less sense to the breathing system. I love old cars. Lol
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Re: Fuel tank breathers question

Post by chewbacca »

Incidentally, my new tank is painted and ready to go once all the grommets are in.
I've not started on the underseal yet. There's great access to the rails though, so I'm glad a got few cans of the dynax s50 for doing those while the tank is out!
Just trying to decide whether to swap the the water pipes first, or underseal first.
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chewbacca
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Re: Fuel tank breathers question

Post by chewbacca »

crazyhorse wrote: What would you advise to blank off breather tanks pipe from tank??

If I do decide to bin the tanks, I'll use a bit of pipe to link the outlets that feed the breather tanks on each side, effectively blanking them off
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R0B
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Re: Fuel tank breathers question

Post by R0B »

Would VW put them there if they were not needed?
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crazyhorse
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Re: Fuel tank breathers question

Post by crazyhorse »

chewbacca wrote:
crazyhorse wrote: What would you advise to blank off breather tanks pipe from tank??

If I do decide to bin the tanks, I'll use a bit of pipe to link the outlets that feed the breather tanks on each side, effectively blanking them off

The plan....maybe is to take the tank out. Buy 1 Can of UB, spary the hell out of that area, take breather tanks out spray the hell out of the wheel arches.

Then to the tank itself. blank off the 2 metal pipes coming from the tank, then with the 2 3 way breather hose from tank, run a small fuel hose with clips and blank them off maybe tie them down on top of the tank. Will see. I know a lot will say this is a no no, but for the amount of time I use petrol might be the way to go. Just need to figure out which pipe blanks to get

Chewbacca, keep me posted, or if anyone has any suggestions if I shouldnt do this
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chewbacca
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Re: Fuel tank breathers question

Post by chewbacca »

I will do mate
I'm currently leaning more on leaving mine in place.
No decision yet though.
I'd splash out on can of the s50. Get the rails filled while the tank is out.

Fingers crossed I'm hitting the water pipes and underseal tomorrow night.
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itchyfeet
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Re: Fuel tank breathers question

Post by itchyfeet »

This is the VW fuel tank test, I wonder how many would pass the test now :D

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Re: Fuel tank breathers question

Post by shepster »

Pull the pipes off and drive around for a few months, if now't happens decide then.

If your van ends up on it's roof do you really think you'll give a sh*t if your expansion tanks are connected?
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Re: Fuel tank breathers question

Post by doowyrag »

Good Evening.

I’ve recently taken my tank / etc out to replace and was going to ask the same question re: the single run of rubber.

It’s seems to make sense to do this and have less connections.

Have you done yours yet, and which route did you go down?

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Re: Fuel tank breathers question

Post by chewbacca »

In the end I left the rigid plastic pipes. Purchased some new metal inserts from brickwerks and cut them down by an inch on each end to ensure a good connection.
I also used a fuel filter with 6/8mm connectors on it. Saves using a reducer, so that's 1 less join.
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