Can you use fernox LS-X to leaking cistern?

cherry76

I have tried everything on my problematic cistern and yet it still leaks drops in the middle where the cistern sits on the toilet. Dynrod plumber has been and was puzzled, he sealed it with sealant but that did not work as water stopped the sealant to set. I have read about fernox LS-X, I wonder whether I can use it to seal the back of the cistern. I am just concerned in case it set hard and then nobody will be able to remove the cistern in case of future problems. There must be a solution to this problem and it is driving me nuts. At the moment, it is either I put a tray to catch the drips or put tissues at the back and change it three times a week. I am also thinking of calling another Dynrod plumber again for a second opinion. Thanks

27col

Fernox LS-X is not the answer to your problem It does not really set hard but It intended for small joints on rigid pipe olives and such like. It can be quite difficult to remove.These low flush systems can be a bit problematical but can be fixed with a bit of patience. The problem is most likely to be the big doughnut washer which sits on the hole in the pan. If it is not seated properly, or damaged in any way then there will always be a slight weep. They can be bought in most DIY sheds. There are two sizes so you would need to buy both and take back the one you did not use.
The other possible source of a leak in the same area is the two threaded screws which go through the bottom of the cistern to fix it to the pan. Some coupled systems do not use the holes through the bottom of the cistern, so this could not be the cause of a leak. This type of cistern uses a special bracket which fixes under the cistern. The only source of a leak in this type of cistern is the doughnut washer. If the joint leaks then it is because it has not been assembled properly, even if the doughnut washer looks ok it would be a good idea to replace it.
Hope this helps a bit.