Fuel tank breathers

[threedogs]

Hi again just watched a piece on 4WD Pro Tips on Fuel Tank breathers.
Has anyone done this and on what model and engine.
I know we all do our diffs , but even this is the first time I've heard of extending the fuel tank breather tubes
Mods feel free to move if its in the wrong section

[Winnie]

Hi again just watched a piece on 4WD Pro Tips on Fuel Tank breathers.
Has anyone done this and on what model and engine.
I know we all do our diffs , but even this is the first time I've heard of extending the fuel tank breather tubes
Mods feel free to move if its in the wrong section

Your fuel tank breathes into the filler neck which is sealed so why move it?

[threedogs]

Guy on 4wd pro tips suggested it would be better extended for some reason.
No idea why

[nissannewby]

Your fuel tank breathes into the filler neck which is sealed so why move it?

They have external breathers mate. They are generally a little plastic looking thing near the filler.

[Winnie]

They have external breathers mate. They are generally a little plastic looking thing near the filler.

Mine definitely doesn't

[nissannewby]

Mine definitely doesn't

They have to breathe mate. If they cant breathe and the tank is completely sealed you will actually starve for fuel as the tank will pull a vacuum and the fuel just stops flowing.

[AB]

Yeah he's right Winnie, you need to replace the space inside the tank when fuel gets taken but the breather is not near the top of the neck on ours. Must be further down the filler or on the sender unit.

[Winnie]

Yeah makes sense... I did not see one when we did our install? Our second tank doesn't have one, but it is breathed to the main tank so could share?

[AB]

Yeah makes sense... I did not see one when we did our install? Our second tank doesn't have one, but it is breathed to the main tank so could share?

Yep that's why there's a breather from main to aux. fuel from aux to main gets air from main to aux to replace space when transferring.

Must be on top of the main tank or sender or in the original filler further down mate.

[MudRunnerTD]

The breather is up next to the filler neck in the wheel arch, it has a 180 bend and faces downwards. It has a larger hose on the end and acts like a Bell. If it went underwater it would create an airlock. I can't think why you would extend it.

[liftlid]

Mine had a white plastic tube thingo on it that filled with mud, that caused the fuel not to suck through to the pump and lack of power and surging. If you open the filler cap and get a whoosh of air the tanks not breathing

[sooty_10]

Mine had a white plastic tube thingo on it that filled with mud, that caused the fuel not to suck through to the pump and lack of power and surging. If you open the filler cap and get a whoosh of air the tanks not breathing

Yeah that's what my cab-chassis had too, until it fell off and got lost.

[04OFF]

I thought all fuel expansion vapours are supposed to go through the charcoal canister as per emission control ADRs on all cars since about 1976 ?

[Clunk]

For those that don't know where to look, rear wheel arch (and yes mine needs a wash)
48223


edit: Sorry, forgot to mention that this is on TD42 GQ, will have a look later to see if the TB42E is the same

[MudRunnerTD]

Perfect pic clunk.

[liftlid]

I thought all fuel expansion vapours are supposed to go through the charcoal canister as per emission control ADRs on all cars since about 1976 ?

Has a one way valve on it air can go in but not out

[04OFF]

Has a one way valve on it air can go in but not out

Yes correct so you dont have a vacuum in the fuel tank, also air may be mixed with the stored fuel vapour (from the charcoal canister) to be burned in the combustion process.

Fuel vapour should never vent to atmosphere, the whole point of having the charcoal canister is to prevent this from happening.

[mudnut]

Well this is a very interesting topic, because my Old Trol's fuel tank has always been under vacuum pressure when I take the cap off. I had a look under the plastic shield and found that the breather is just connected to the top of the filler. There are only three other hoses connected to the tank: Fuel out, fuel return and the breather hose. Sometimes, after a long drive, there is a weird noise, like a valve opening and air being sucked slowly through a pipe. I will have to search deeper to find out if this is normal for a petrol Patrol. The picture is of the back of the filler pipe where the breather joins it.

Edit: Just clarify it further, this picture is not the breather, but part of the filler system as noted in E.T's reply below.

[AB]

Bloody hell Winnie we must have the worst memories...lol

Look at the picture that clunk put up. Do you remember we saw that when doing the aux tanks and figured it was the breather.

Do you remember I had to bend mine a bit as it was rubbing against the dual neck?

Hopeless, absolutely hopeless!!!!

[the evil twin]

The confusion in this thread is because the -ve pressure breather is in different places on different models.

The pic that Mudnut has posted is not the tank breather... on a GU anyway.
That pipe is part of the filler neck assy and is there to stop hydraulic locks and blow back when you are filling the tank
It allows air to leave the tank as fuel flows down the filler and doesn't serve any other purpose.

In many of the early GU variants the breather is just beside the Fuel Tank Sender Unit.
It's a small placcy doover about the size of a small inline fuel filter.
They have their own pipe to the tank and are held in place by a small bracket.

There is a good piccy of the location on page FE 24 of the factory manual.
It isn't labelled in the pic or referred to in the Fuel System Chapter.

In other models it is up where Clunk has posted his pic.

I can't be arrsed looking up all the references for later models/variants but they have to have one somewhere as others have mentioned

PS... please don't ask me why the fuel caps have a +ve and -Ve pressure release as well... I don't know.
Perhaps it's a belt and braces thing.

PPS ... as I acknowledged to Mudnut... GQ's may be different, I'm not sure how they are plumbed.

[Clunk]

The confusion in this thread is because the -ve pressure breather is in different places on different models.

The pic that Mudnut has posted is not the tank breather (sorry Cobber) .
That pipe is part of the filler neck assy and is there to stop hydraulic locks and blow back when you are filling the tank
It allows air to leave the tank as fuel flows down the filler and doesn't serve any other purpose.

In many of the early GU variants the breather is just beside the Fuel Tank Sender Unit.
It's a small placcy doover about the size of a small inline fuel filter.
They have their own pipe to the tank and are held in place by a small bracket.

There is a good piccy of the location on page FE 24 of the factory manual.
It isn't labelled in the pic or referred to in the Fuel System Chapter.

In other models it is up where Clunk has posted his pic.

I can't be arrsed looking up all the references for later models/variants but they have to have one somewhere as others have mentioned

cheers ET, have edited my post accordingly to prevent confusion for owners of other models.

[mudnut]

Thanks, ET. I will have another look tomorrow. Obviously there is a problem with my set up. The breather must be blocked or the pipe crimped somewhere. My Old Trol is an RB30 '94 model if anyone has further info for me.

[the evil twin]

Thanks, ET. I will have another look tomorrow. Obviously there is a problem with my set up. The breather must be blocked or the pipe crimped somewhere. My Old Trol is an RB30 '94 model if anyone has further info for me.

Onya mate... I must admit I am not familiar with the GQ's so I'll nip back and clarify my post.
I've never had to replace one on any of my GQ's but the valve on my GU Uterus was a bit of a PIA when I fitted the Long Ranger tank

[nissannewby]

Onya mate... I must admit I am not familiar with the GQ's so I'll nip back and clarify my post.
I've never had to replace one on any of my GQ's but the valve on my GU Uterus was a bit of a PIA when I fitted the Long Ranger tank

Is that a special edition GU? Does it require routine drain intervals? If it leaks do you just block it with a tightly spun cotton plug?

:) I believe they are a utility lol.

[the evil twin]

Is that a special edition GU? Does it require routine drain intervals? If it leaks do you just block it with a tightly spun cotton plug?

:) I believe they are a utility lol.

Nope, not mine...

If I may quote
"The main function of the uterus is to carry, protect and provide nourishment to the developing baby."

That pretty much describes me and mine to a T.

:driving2::driving2::driving2::driving2::driving2:

[nissannewby]

Nope, not mine...

If I may quote
"The main function of the uterus is to carry, protect and provide nourishment to the developing baby."

That pretty much describes me and mine to a T.

:driving2::driving2::driving2::driving2::driving2:

Thats fine. Either way you look at it a uterus is still part of a females anatomy.

Just to be sure I wasnt intending insult, just one of those little things that annoys me just like when they are referred to as trucks lol

[mudnut]

I had the carpet up and the fuel cover open to check something to do with the fuel pump today, and I traced all of the hoses that come out of the tank.

There seems to be no breather as such, there is a valve in the vapour canister line. The canister has a vacuum control diaphragm and a hose for the fumes to be drawn into the engine.

I have sometimes heard a momentary, weird noise as if air is being drawn past a restriction when the Old Trol is sitting under the carport. I suspect this valve may be not operating as it should as I still have a strong vacuum in the tank.

[Mjcpatrol]

You will find you not allowed to let it breath to atmosphere

[Mjcpatrol]

Back in 1974 they stop that