This month we’re back in the bathroom with a leaky toilet. This time it’s an external leak (meaning that there's water on the bathroom floor) which, as we saw in the previous leak detection post, gives 2 basic possibilities:
1. Leaks from the cistern – the toilet refills continuously and refills continuously causing an ever increasing amount of water on the bathroom floor.
2. Leaks from the bowl or outlet – the toilet leaks during or after the flush leaving a small puddle on the floor. The quantity of water is limited since the cistern doesn’t refill.
The possible sources of these types of leak are:
1. Leaks from the cistern
a. Cracked or damaged cistern
b. Leaky seal between the cistern and the pan
2. Leaks from the bowl or outlet
a. Cracked bowl
b. Leaky toilet seal or flange
Cracked cisterns or toilet bowls can be repaired with an epoxy filler or repair-all type putty.
Damaged seals or flanges need to be replaced
Sometimes a good seal leaks because the cistern or bowl isn’t firmly fixed in place leak because of movement. Check the bolts which hold the cistern to the bowl and the bowl to the floor are correctly tightened. A toilet or cistern which rocks will often leak.
Visual inspection will show which of the causes mentioned above are to blame.
In this case we find drips coming from the toilet pan outlet seal. Closer inspection reveals that the rubber is perished and cracked. The solution is to replace the seal with a new one.
How to Replace a Leaky Toilet Seal
Toilet Repair Step 1
Fill a bucket, the sink and the kettle with water. We’re going to turn off the water at the main stopcock so we’ll need water to clean up, wash our hands (believe me you’re going to want to wash your hands several times during this process!) and of course make a cup of tea!
Toilet Repair Step 2
Turn off the water at the stopcock – there may be a small tap mounted on the wall at the inlet to the cistern, but in my experience these valves frequently leak. It’s always best to turn the water off at the stopcock.
Flush the toilet to empty the cistern, undo the two plastic wing-nuts which connect it to the toilet bowl and lift the cistern clear (empty any residual water into the bath or the toilet and put the cistern carefully to one side)
Remove the seal between the cistern and the toilet bowl. Depending on its condition you can either re-use it or replace it with a new one (Even thou the existing seal didn’t leak I decided that it would be a good idea to replace it with a new one when reassembling everything – preventive maintenance)
Unbolt the pan from the floor. The are two bolts which fix the pan to the floor. We use a 10mm spanner to remove the cap-nuts. It’s possible that the nuts have corroded onto the bolts in which case the bolt will most likely release from the rawlplugs in the floor. If by a stroke of bad luck they don’t release easily from the rawlbolts in the floor then you may need to cut the nuts off using a dremel (or similar tool) and mini cut-off disk.
The Toilet pan can now be lifted clear of the 2 fixing bolts and pulled away from the waste pipe.
Tip the water from the toilet bowl into the bath.
Remove the damaged toilet seal and (in order to ensure that the new seal seals) clean up both the outlet from the pan and the entrance to the waste pipe. Believe me, you will want to wash your hands after doing this!
Remove the bolts from the floor; this is best done with mole grips. Take care not to damage the threads when doing this.
Fit the new seal to the waste pipe and slide the toilet bowl into place, taking care to make sure the seal seats correctly against both the waste pipe and the exit from the toilet bowl.
Replace the nuts and bolts which hold the toilet pan in place. Tighten down each side bit-by –bit to make sure that the toilet is correctly aligned and firmly seated.
Empty the bucket of water into the toilet to perform a test flush and ensure that the new seal doesn’t leak. If it leaks, it will be necessary to disconnect the bowl again and re-seat the seal.
If the toilet doesn’t leak then we proceed to re-connect the cistern and open the stopcock.
Perform a test flush to make sure that everything works correctly and that there are no leaks.
Clean up any mess and wash your hands!
Alternative Types of Toilet Seal
The rubber seal shown in the photos is very common. You may also encounter more elaborate seals or the old fashioned wax seal. In the case old the wax seal we simply cut the donut into two pieces, insert the two parts into the gap between the toilet and the waste pipe. We then use the heat from our hands to mold the wax into place until a hermetic seal is formed. The other plastic seal is simply inserted into the drain pipe and the toilet is slotted into place. Another possibility is that the toilet sits on-top of the waste pipe and there is a seal in a flange which is fitted into the floor below the toilet. These types of seal are similar to those which we have seen and the symptoms and replacement process are basically the same as described above.