# Breather for fresh water tank



## cyclops2 (Oct 15, 2010)

My 1998 Duetto has a 16 gal water tank. It has two breather holes on the top of the tank which you fill until water runs out. I find that it runs out for a lot of miles after,every time you are on a slope. I am fed up leaving a trail behind me frankly it is also embarrassing. I wondered if the dealer had forgotten to connect breather tubes when new tank fitted or perhaps using the wrong tank but contacted autosleepers today and was told that was correct for my model. There is a pipe connected to the top of of the filler pipe which allows air into the filler pipe. I reckon this would allow enough air into the system for normal usage. However there would still need a vent to tank when filling. I'm looking for advice. I think that if the filling tube is left with no U bend and goes directly to the tank that would work for usage but how to sort the filling of tank?


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## Basil (Oct 15, 2010)

*Possibly Syphoning....*

I have read quite a few posts over the last 12 months about this sort of thing happening....
I wonder if it could be syphoning through the breather pipe....
Seems the only conclusion for it to keep pouring out for quite a time....


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## Basil (Oct 15, 2010)

*Test*

To save re routing pipes, could you fit an in-line on/off tap in the breather pipe and turn off while driving.... That would either confirm or eliminate....


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## Deleted member 5816 (Oct 15, 2010)

*Fresh Water Tank Breather*

This type of tank breather is common to all Auto - Sleepers if it bothers you that much either run off a few gallons from drain tap after filling or dont fill as much.

You could always park with the nearside wheels on the curb for 1/2 hour or so.

If you sealed breathers on tank you would have a problem filling tank unless you slowed filling to just above a trickle


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## Basil (Oct 15, 2010)

*Work the tap*



Alf 1 said:


> This type of tank breather is common to all Auto - Sleepers
> 
> If you sealed breathers on tank you would have a problem filling tank unless you slowed filling to just above a trickle



 the open tap would allow breathing while filling.... and close tap for driving..... No water should come out then.... I hope....


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## vwalan (Oct 15, 2010)

some tanks have a small breather fitted on top of the tanks .its very small and like a one way valve but sometimes it will allow water to exit untill the water is not in the filler pipe . i think its the weight of the water is just too much for the valve. mine as done it since new .i fitted the tanks and have them down to make sure all was tight. they are cak tanks . just dribbles out till water gets to correct level. annoying but i can live with it.


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## Byronic (Oct 15, 2010)

The various fresh water tanks I have fitted always had an anti airlock 10mm dia spigot  
situated on the top surface of the tank and I connected this with the appropiate tubing 
to the spigot at the filler cap this means that if the van was on a very steep slope any water in the anti air lock pipe would run back down the filler pipe.


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## Deleted member 5816 (Oct 15, 2010)

***** said:


> The tap idea makes sense, however there must be someone on here with a similar van that has rectified the problem


 
On the auto-sleeper fresh water tank there is 2 small breather holes on the top of the tank this is to alow air to escape as the tank is filled if the tank is overfilled that is to the water inlet point this is a 1 1/2 pipe about 2ft long this extends above the top of the water tank this may hold say a gallon of water this then has to escape and trickles out of the tank breather if the OP is bothered about this its only a matter of Not over filling or just open fresh water tank drain tap and dumping a couple of gallons.

I have seen these holes sealed and seen the water inlet hose blown off by air compression due to inlet water pressure

I might add many years ago I had a Sherpa Auto-Sleeper the water filler was under the bonnet in the engine compartment it had about 8ft of the wide filler pipe so it dribbled for ages when overfilled

Alf


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## jogguk (Oct 15, 2010)

Bung up the breather holes on the tank, May get away with some rubber blanking grommets? Then drill a small hole in the filler cap to vent the tank. The tank needs venting otherwise it will collapse when the water pump sucks the water out

Alternatively, run a small dia. tube from the breather hole to a location close to the filler cap.

John


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## Mastodon (Oct 15, 2010)

My filler cap has a breather built in with a spigot on the back. I connected a tube to this and fitted it into the water tank through a rubber grommet, then put a bung with a float round it into the overflow pipe. This is attached by a thin bungee cord down the middle of the tube (still with me here?) to the underside. In normal use the bung can float free and allow the tank to overflow, for use in hilly terrain, the bungee is pulled tight to seal the overflow. The new breather allows for pressure changes. SIimples


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## Tony Lee (Oct 16, 2010)

To fit water tanks without an elevated breather pipe is just lousy design/poor workmanship and penny-pinching. The result is people filling their tanks and arriving at the campsite with tanks half-full. Alternatively, the manufacturers push a bit of pipe several inches inside the tank and just let it hang and that results in most of the contents siphoning out.

Correct method is to either connect a vent pipe to the vent spigot at the top of the tank if one is fitted or if it is a cheap tank, drill a very snug-fitting hole in the side of the tank as high as possible and force the vent tube in an inch or so. The vent pipe is then run without any dips either to the vent opening often incorporated into the gravity fill fitting on the side of the van, or up into a wheel arch to a point higher than the top of the tank. Ideally the pipe should be curved over an inch or so, so it points down and a bit of insect screen tied over the end to prevent the mud wasps from blocking it up.

If there is a choice of vent holes, use the one on the opposite side to the filler pipe and block the other one off.

Any dips in the pipe will result in the dip filling with water and causing an air lock when filling.

Another trick to allow faster filling - but needs to have a separate vent pipe fitted - is to push the end of the hose right down the filling tube and even into the tank if possible. This stops the annoying blow back that occurs when air needs to escape back up the filling tube.


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## Deleted member 5816 (Oct 16, 2010)

Tony Lee said:


> To fit water tanks without an elevated breather pipe is just lousy design/poor workmanship and penny-pinching. The result is people filling their tanks and arriving at the campsite with tanks half-full. Alternatively, the manufacturers push a bit of pipe several inches inside the tank and just let it hang and that results in most of the contents siphoning out.
> 
> Correct method is to either connect a vent pipe to the vent spigot at the top of the tank if one is fitted or if it is a cheap tank, drill a very snug-fitting hole in the side of the tank as high as possible and force the vent tube in an inch or so. The vent pipe is then run without any dips either to the vent opening often incorporated into the gravity fill fitting on the side of the van, or up into a wheel arch to a point higher than the top of the tank. Ideally the pipe should be curved over an inch or so, so it points down and a bit of insect screen tied over the end to prevent the mud wasps from blocking it up.
> 
> ...



Tony originaly Auto-Sleepers on their van conversions had a tank with a baffle plate in the center of the tank they put an 1/8 " breather at each side to allow air to escape, the original conversions had a water filler under the bonnet.
All the current van conversions also have 2  - 1/8" holes on the top of the tank for breathers to look at these would mean removink the tank if yo overfill the filler yube is full of water and this drains off via the breathers if you are on a steep slope with a full tank you get a dribble if it a problem it is easy to run a bit of water off from the fresh water drain tap.If you block these breathers you end up with the tank 1/3 full of air instead of water

From 1969 we have had 12 Auto-Sleeper van conversions and never any problem with water dribble the only other problem was water loss over Hard Knott pass and The pass of the Cattle but thats another story   

Today I filled our tank brim full in the time it took to put some things in van and lock up etc the dribble had finished I drove a couple of hundred yards stopped to have a look no water dribble if the OP is getting a dribble for longer than this there must be other problems a typical Auto-Sleeper problem is the fresh water tank drain tap this is fixed through the tank wall and a locknut inside the tank sealed with a blob of mastic it is nearly an impossible task to tighten once loose as the locknut spins.


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## Tony Lee (Oct 16, 2010)

Thanks Alf, I suspected something like that. Penny pinching!

I can understand the OPs concern at having water running below the van. Apart from the total waste of scarce water capacity, he is also embarrassed about it. In some countries it may even be illegal. Perhaps he doesn't want to be thought to be one of those RVers who drive around with their grey tank dribbling out on the road to avoid having to empty it.
As you said,a proper fix is going to require a bit of work and only he can decide whether it is worth going to the trouble.


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## cyclops2 (Oct 17, 2010)

Thank you all very much for your comments. Just to clarify a few points . It has 2 holes about 8mm diameter in the rear end of the top face of the tank which is about 4 ft long and 8 in deep. If it is any incline at all water pours out of the holes. If this is the only problem I have with my van I will be very lucky indeed but it still annoys me and apart from anything else is not hygenic. As someone said for the sake of a couple of pounds during manufacture this could have been sorted. 
I will probably connect a pipe from the top of the tank to the drain pipe that comes from the back of the filler making sure that it wont hold any water. I will then have to get a vented cap for the filler. Thanks again


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## Tony Lee (Oct 18, 2010)

Yes, a 10 degree slope and you lose half your water - and with 2 x 8mm holes, at quite a rapid rate. Certainly more than a dribble

With a bit of luck you will be able to get some tubing that is a tight push fit into the holes and solve the problem. Just don't push the tubing too far into the tank.


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## cyclops2 (Oct 20, 2010)

Thanks Tony, one point that I didn't make was that the dealer replaced the water tank just before I bought the van. It is highly probable that it is not the correct one for my model. Perhaps later ones had breather pipes connected hence the larger holes
Pete


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## Deleted member 5816 (Oct 21, 2010)

*Water Tank Breather*

So this is not cheap and shoddy work by Auto-Sleepers but by the selling dealer fitting a non converters replacement fresh water tank.  

 perhaps you could try a piece of gaffer tape or similar over the existing holes and peirce with a small nail to allow breathing, if this works you could look for a permanant solutuion


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## cyclops2 (Oct 21, 2010)

Not jumping to any conclusions yet but that is a possibility. Might be a Duetto tank but more modern than my 1998 one. Noticed that the plywood underneath is much longer than the tank. Have taped one hole up and put pipe in second went for a drive and no apparent leaks at moment
Pete


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## Deleted member 5816 (Oct 21, 2010)

*Water Tank Breather*



cyclops2 said:


> Not jumping to any conclusions yet but that is a possibility. Might be a Duetto tank but more modern than my 1998 one. Noticed that the plywood underneath is much longer than the tank. Have taped one hole up and put pipe in second went for a drive and no apparent leaks at moment
> Pete



cyclops2 

Good lets hope your problem is now solved    

Alf


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