leak from back to wall toilet at inlet pipe from cistern ?

Hi JC,
Sounds like you may have the kind of toilet I have just fixed. Hardly any room at the back to work. If, as you say, the leak is at the inlet pipe to the cistern I had the same problem. My toilet is an Ideal Standard close couple unit with Geberit Twinco Flush Valve (two buttons on top to flush) and the water supply comes into the cistern through an inlet pipe at the bottom. Inlet pipe connects to the inlet float valve which is mounted vertically in the Cistern. My leak was either at the inlet pipe seal at the bottom (inside) of the cistern or at the fibre washer seal at the junction of the metal inlet pipe where it meets the plastic vertical inlet pipe part of the inlet float valve mechanism. Not sure how a radweal type product would help you - it might just block the whole water flow!! I fixed my problem by:
1. Turn water supply to cistern off at the inlet pipe - small in-line tap/valve which you may have to turn with a small flat screwdriver. If no in-line valve - turn off at the mains.
2. Flush to empty cistern and sponge out the remaining water.
3. Disconnect inlet valve pipe from below (very difficult - I had to buy a special long reach spring adjustable spanner).
4. Remove the top of the Inlet Float Valve mechanism leaving just the plastic pipe sticking up vertically.
5. Remove the vertical plastic pipe from cystern - by unscrewing plastic nut below. Replace (black) rubber seal on this pipe if damaged.
6. Replace fibre (Red) seal at the inlet (metal pipe) connection below the cystern - my original one was deformed so this was probably where the leak was.
7. Re-assemble and re-connect in reverse - using some vaseline to lubricate the plastic pipe and black seal where it fits into the cistern. Also the bottom thread of the plastic pipe where the metal pipe connection will screw back on. Ensure the (red) fibre seal is carefully positioned in the connection before re-connecting the mains pipe and tightening hand tight.
8. Tighten the connector with the same spanner but only 1/4 turn.
9. Water on and check for leaks.
The above sounds easy - but I am Not a plumber and it took me 90 mins of struggle and swearing at the designers of these toilets for making things so inaccessible. The only way I could see where the (red) fibre seal had to go was to look vertically down throught the hole at the bottom of the cistern and position it correctly before replacing the float valve and pipe in the cistern.
Sorry if this makes no sense at all as you probably have a totally different toilet to mine!!
Good Luck
Michael K

Michael K
January 2011