How to Fix Toilet Cistern Flush

tools on a toilet tank
  • 1-2 hours
  • Intermediate
  • 5-50
What You'll Need
Replacement components
Rubber gloves

Being able to repair a toilet cistern flush can be useful if you suddenly discover that it is not working. Rather than contacting a repair technician, follow the steps to repair the toilet and save yourself time and money.

Step 1 - Inspect Toilet

It can often be the case that the only evidence you get of a toilet cistern flush being defective is when you make an attempt to use it but nothing happens. Where this is the case, you will need to investigate further to determine the cause of the problem.

The two main causes will be a broken or dislodged connection between the flush handle and the flushing mechanism or a defect in the flush diaphragm. Remove the cistern lid and carefully set it aside so that it is not at risk of being stepped on or falling over.

Step 2 - Repair Handle

Where the toilet cistern flush handle is no longer connected to anything or the handle has dropped, it can be replaced without having to disconnect the water supply. In the event that the handle has dropped, the connectors may have worn and will have to be replaced.

After removing the wire connecting the handle to the mechanism, use a wrench to remove the nut holding it in place. Withdraw the handle stem from the hole in the cistern and replace it with a handle kit that is of the exact same specifications.

If the wire connector that links the toilet cistern flush handle to the internal mechanism has corroded or failed in some way, this can often be rectified simply by replacing this component. After undertaking the repair work, test the flush while the lid remains off to make sure it works properly.

Step 3 - Replace Toilet Syphon

person working on a toilet tank

If the toilet cistern flush handle is intact and working correctly, the problem is likely to lie with the flush diaphragm which is at the base of the toilet siphon – the largest section of the mechanism within the toilet in which water is drawn in and flushed out.

If you have the original manual, it will be useful to have this to hand to help to recognize the assembly. Begin by disconnecting the power supply to the toilet and flushing it or bailing out the water until the cistern is empty before using a rag to soak up any last traces of water.

Once empty, locate the clips that hold the flush handle to the syphon and the syphon to the rear of the cistern. The entire mechanism can then be lifted out of the cistern, which will probably be the first occasion in which you will properly see the split. The entire toilet mechanism can be purchased in a kit which will comprise all the components needed for replacement.

Reassembling the mechanism will involve simply reversing the procedure used to disassemble it. After reconnecting all the fasteners and components, turn the water supply back on and watch the cistern refill with water to ensure that there are no further problems.