Broadway Fresh Water Tank Leak

For sometime now I've been trying to cure a water leak where the pipe goes in to the tank (apparently known as the drain union?). I've used all sorts of silicon seal but can't seem to find any that do the job 100%.
Any ideas gratefully received.
Thanks

If its leaking from the male iron thread remove it and wrap some PTFE tape around the thread and replace.

Graham

Hi Graham,

This is the rigid pipe that runs from the drain tap in to the tank. There is a plastic nut which cannot be tightened as it just turns round. Every time I open the drain tap the whole pipe turns, according to Marquis the only way to resolve is to drop the tank and tighten from the inside, their other method is to slap silicon around the pipe where it enters the tank and hope it lasts.
Although Marquis found the leak during the Hab Inspection they didn't offer to fix it although the van has to go back for warranty work, I don't really want them to drop the tank so I will try some alternatives.

Andy

Andy, I had same problem on same model of Broadway as you. Mine was sorted by an external application of a very good sealant called Plumbers Gold. When I was looking into the route cause I found that the tank support braces where not sufficiently tight and thus the tank was moving about slightly whilst driving - especially if you have it partially full.
Check the braces (hook bolts) for tightness by leaning under the van an see if you can move the tank.
Tank movement is what causes the joint to leak, since the outlet pipe is fixed at the other end.
Incidentally I had the same problem for the same reason with the waste tank.
It is best not to travel with too much onboard water anyway.

Yes plumbers Gold might fix it but I guess if the tank is flexing in the straps that problem needs addressing. It is must be a male threaded fitting with a back-nut the other side that is loose and keeps turning so the permanent fix is to drop the tank remove the fitting and put correct size rubber washer on the outside of the tank wall with a smear of silicon and tighten up.  It is a bit of an awkward job and I would ask them to do it under warranty as it is faulty workmanship.

Graham

Thanks both,

I've also found there is too much flex in the pipe as the only point where its fixed is at the drain tap by a flimsy bracket and clip. I've used some straps to tension the pipe to a chassis bracket and thats stopped a lot of the movement when opening/closing the tap.
Re-sealed around the nut with Sikaflex sealant and will fill the tank in a day or so and see what happens.

I have had the same problem, I strengthened the bracket (used thicker metal). I cleaned the old sealant from around the union and used black roof and gutter sealant from the local pound shop. Seems to have worked better than the expensive sealants. Have also done the waste as well.

Filled the tank today and the tiniest drop of water seeped through so have re-sealed again. Its only when you're under the van you see where money is saved and corners cut.