# Fresh water tank sensor loose



## garethjjones (May 1, 2005)

Hi, 

Our 2004 Hymer has a fresh water tank with a Schaudt M600 sensor fitted. It's come loose, so I can rotate it in it's fitting. The problem is when we fill the tank right up, it also leaks water.

I'm trying to tighten the bolt/washer - but it's very hard to get at, and I can't work out the size of spanner I need. Any ideas?

phone photo attached (what did we do without the ability to take pictures like this). If I can get the right spanner size it might be possible, but once I've got the adjustable in and my hands, there's no space for a camera as well.


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## 747 (Oct 2, 2009)

There are 2 ways to tighten it.

Get some water pump pliers http://www.screwfix.com/c/tools/water-pump-pliers/cat831210 and if you can tighten the nut with them, all well and good. Sometimes it is just not possible due to limited space and you not being a contortionist. :smile2:

The second method is to run the nut up as tight as you can by hand, grip the nut with your hand and tighten the body of the sensor from the outside of the tank. It only needs a decent nip to seal it (assuming you still have the washer on the outside).

If I were you, I would clean the sensor prongs with a pan scrubber (or similar) while it is loose, then refit it properly.


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## garethjjones (May 1, 2005)

Actually, I have some of those, somewhere in the shed! I'll try that.

It's very difficult to get a grip on the nut, where it's positioned, so I've tried to get a grip by hand and rotate the fitting - but no joy hence the requirement for some grips and some leverage.

Supplementary questions -

The top view of the tank is shown below. The sensor and pump fittings are labelled. What's the other pipe coming out of the tank - a breather pipe, or the overflow. I have an overflow fitting in the LHS locker - same as mentioned in this post but it's never been opened in the 10 years we've had Harry! If this was used (open) then the tank wouldn't fill to the extent that the sensor leaked - but perhaps we would have less water to use.


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## 747 (Oct 2, 2009)

Seems like an overflow. If so the other end of the hose will go through the floor and be an open end.


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## hogan (Oct 31, 2006)

garethjjones said:


> Actually, I have some of those, somewhere in the shed! I'll try that.
> 
> It's very difficult to get a grip on the nut, where it's positioned, so I've tried to get a grip by hand and rotate the fitting - but no joy hence the requirement for some grips and some leverage.
> 
> ...


The first picture is the overflow for the fresh tank.
Second picture is a valve that can be opened so you cannot fill the fresh tank more than half full.This was because some Hymers had a very low payload hence a poss 50 kg weight saving device.


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## dalspa (Jul 1, 2008)

The connection on the top of the tank (marked as overflow) is, I think the breather. However, if you filled up by running a hose into the external filler point then the "breather" would act as an overflow when the tank is FULL (eg. if you were distracted during the filling process). The one on the side of the tank is more of an emptying valve to half empty the tank, for using in conjunction with the rubber bung in the bottom - to empty quicker and saving getting more of your arm wetter if the bung hasn't got a chain attached. I rarely use this side valve on ours. As you said, if the one on the side was used as an overflow then you would only start with half a tank.

DavidL

Edit. Following Hogan's post (while I was typing), I've learnt something. Thanks. Have owned Hymers for 10yrs and I didn't realise that.


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## philoaks (Sep 2, 2008)

garethjjones said:


> Actually, I have some of those, somewhere in the shed! I'll try that.
> 
> It's very difficult to get a grip on the nut, where it's positioned, so I've tried to get a grip by hand and rotate the fitting - but no joy hence the requirement for some grips and some leverage.


Not sure of the size of the nut but would something like a plumbers shetack wrench help?


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## garethjjones (May 1, 2005)

Thanks for all the help and advice.

Managed to get a pair of grips on the bolt, but couldn't get the sensor to tighten (or loosen). 

So, pragmatically I've put some silicon sealant around the sensor hoping to just seal the gap, and leave it at that. We'll seed how it goes. 

I wonder though how it became loose? I checked the waste tank and the sensor there is fixed solidly.

I've now moved onto fixing the drawers so they don't fly open in transit


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## iandsm (May 18, 2007)

You can but from a motor spares shop, perhaps Halfords, a putty that you mic yourself that is intended to repair plastic fuel tanks. I used some to seal a cable coming into out roof from our solar panel. It sets rock hard and can be used when the surfaces concerned are wet. My piece has been in place for 12 months rock solid and no signs of leaking. There is also sikaflex too which would probably do the job if you just want to seal it.


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