Waste Water coupling leak

[chasm]

Our Hymer C544 Swing is now 13 years old and bits are failing. I've just discovered that the coupling between the external waste water tank and the shut-off valve is leaking. Throughout the winter we normally leave the valve open and drain into a bucket or a gozunder to avoid freezing problems.

Just recently noticed that water was leaking fro around the coupling when the valve was shut and there was water in the tank. It's hard to see how the valve is connected to the tank and which parts should be unscrewable or could be prized apart. The weather here in France is cold and wet and not suitable for scrabbling around under the van, so I can't get to grips with problem so to speak.

Does anyone have any knowledge of how the arrangement comes apart: I'm obviously worried that I've got a cracked outlet on the tank.

Here's a photo (I Hope)

[Derek Uzzell]

Your photo suggests that the leak is (as you fear) from where the water-tank’s outlet joins to the tank. This diagnosis is based on the white marking that has built up beneath the tank-to-outlet joint.

 

I’m guessing that the large grey fitting with a knurled ring is attached via a rubber seal to a ’stub’ from the tank - that it employs the attachment method that’s common in domestic waste-water plumbing and that rotating the knurled ring compresses the rubber seal.

 

You haven’t said how bad the leak is, nor how long you’ll be abroad, but I’d be tempted to try a crude bodge-up ‘fix’ rather than attempt to disassemble the fitting, as - if the tank-to-outlet joint is damaged - there’s every chance doing that disassembly will make matters worse. If you can stop the leak temporarily, you can deal with the problem properly when you get home.

 

I suggest you visit a large DIY store and ask what they can offer that can be applied externally to water pipework to stop it leaking. There are various products on the UK market that might do the job (I’d probably go for Fernox LS-X) but I don’t know what’s available in France.

 

Assuming that you can get a suitable sealant, empty the waste tank completely, use leveller wedges to tilt the vehicle so that any water left in the tank runs away from the outlet joint, carefully clean as much ‘crud’ as practicable from around the the tank-to-outlet joint, and then gob plenty of sealant around the joint. If that fixes the leak, be a bit careful subsequently when draining the tank to try to minimise stresses being placed on the joint.

[StuartO]

The man whi can probably tell you is Peter Hambildon because he's bound to have come across this and will know how to fix it. Pter only works Tuesday to Friday these days, so choose your moment to ring. The number is 01772 315078. The phone will be answered by Rose, who like to protect peter from too many calls, so be prepared to say you are in France with a problem, then you might get a quick chat.

 

In the meantime I would leave well alone because of the risk of breaking off the tank fitting or at least opening up the leak. There are a range of special solvents which can be used to weld plastic but you need to know which one to try to use for which type. Peter might know. There's a fair chance that the jointing solvent sold to fix plastic waste pipes in B&Q will do it but there are different sorts, so best check if you can.

 

Alternatively contact CAK tanks, they should know.

[chasm]

Thank you both for your advice. We can live with the problem for now, so I won't try anything heroic which might make the problem worse. From the photo you can see that we've been unaware that we were dribbling waste water everywhere when on the move. I'll follow up your suggestions and will try phoning Peter Hambleton when we get back to UK.

[Patricia]

I had a problem with my waste tank last year and embarrassingly streamed water as I moved the van. Fortunately my caravan technician managed to cure it quite quickly. My fresh water tank drips at the top as I fill it but not too worried about that.