Opening a sealed fresh water tank lid

Hi Folks,

The water filler pipe (from the external filling point to the tank) has developed a leak and I have to replace it. I need to undo the elbow joint on the 120 litre tank in order to move the tank away from the pipe so that I can replace it.

The problem is that the large cap on the top of the tank is firmly sealed and I have been unable to budge it. I have tried heating it and using leverage to unscrew it but all to no avail.

If I am unable to remove the cap I won't be able to undo the nut on the inside of the elbow and move the tank away to allow me access the filler pipe. I am afraid of damaging the tank or the lid

I know the setup is much the same on many motorhomes but I have attached a photo just to be help understand the problem.

Thanks for any suggestions received.

Thanks Mark for that suggestion. I didn't have a rubber mallet but I did make a device out of a piece of soft 2X4 and cut teeth in to it. With some help from some WD40 and the bit of leverage supplied by the 4X2 I managed to get it to unscrew. It was seriously tight though. It was then an easy job to remove the elbow from the tank and then get the elbow off the pipe.

Next comes removing the water filler part on the outside and then withdraw the whole pipe for replacement. I'll look at that part tomorrow.

It has to be very unusual for a pipe like that to leak. I've attached a photo of the pipe with a drop coming from the it at the point where it was leaking.

Very speedy edit after that error. Sorry Mark.

The leak is actually from the pipe itself. It is just where the water drop is coming from in the photo. The pipe definitely has a manufacturing fault.

Good to hear that Mad Max - many thanks for that.

Good to hear you are all sorted.

Great news David.