Introduction: Fix a No Flush Problem

About: I'm an ex IT professional and now enjoying retired life. The most stressful part of my day these days is feeding the chooks and mowing the grass on my mini tractor. I have always been a tinkerer and handyman a…

If you have a toilet suite fitted with an internal wall cistern and it no longer flushes when you press the button, you may find this instructable informative in what I did to fix my problem.

Don't be daunted by the fact that you only have access through a small hole in the wall to carry out repairs, as I can honestly say, that this is the easiest cistern fix by far, that I have ever worked on.

My system is made by Grohe, but I'm sure all brands would operate in a similar way and be just as easy to remove and replace.

When you stop and think about it, maintenance on these internal systems has got to be easy, as you can't be expected to rip off all the tiles and demolish the wall behind when things go wrong.


The only supplies I needed for this project was a replacement hose 2mm ID - sourced from my local fishing tackle shop.

Also available on EBAY -

Step 1: Removing the Cover Plate

The cover plate is easily removed by lifting the plate up from the bottom and pulling out towards you. The plate is held in position by two expandable plastic clips (as shown) which push down on the cover plate locking it in place.

Disconnect the tube connecting the button to the discharge unit.

Step 2: How It Works

The flush system works by air. You will notice that there is a bellow behind the flush button. When you flush, air is passed down the tube releasing air bubbles below the discharge valve causing it to lift and hence flush the toilet.

Step 3: Diagnosing the Problem

Before delving any further into pulling your unit apart, I would first check that the bellow hasn't any holes in it allowing the air to escape. I checked mine by pushing the flush button and ensuring that air was coming through the small aperture at the back where the tube was connected. If all appears to be well with the bellow, we need to disassemble the unit further.

Step 4: The Only Tool You'll Need

This is the only tool you will need to pull the whole thing apart. How good is that.

Step 5: Dismantling the Unit

1. Turn off the water supply by turning off the small tap on the inlet pipe, and then removing the flexible inlet pipe with a 'shifting' or 'open end' spanner and tuck it up out of the way.

Discharge the water in the cistern by lifting up the discharge valve.

2. Remove the float valve by lifting up the small tab at the front and pulling towards the centre of the tank. Take care not to damage the float when manoeuvring this out through the hole as it is only made of polystyrene.

3. With that out of the way, we can now remove the discharge valve. The Discharge Unit comes in two parts. With a slight twist to the left (anti clockwise) the top of the unit should come loose and you can now remove. The lower part of the unit sits in the bottom of the water tank just like a plug, so it is just a matter of pulling up on this and removing from the tank as well.

I couldn't see any purpose of having the discharge unit in two pieces other than to allow for easy removal.

Now that you have the lower part of the discharge unit out in the open, you would have noticed that the other end of the tube had either come adrift, or was fitting loosely as was the case with mine.

Step 6: Sourcing Replacement Parts

If the bellow had a hole in it you may be able to fix with a patch, but I'm guessing that it would most likely be on one of the ribs, in which case I would be looking for a new bellow.

Same with the hose, which for me had lost its elasticity and gone brittle over time. I could be wrong, but I would imagine Grohe would charge an arm and a leg for a replacement hose, so I went hunting for a cheaper alternative.

The tube I needed would need to have an internal diameter of about 2mm. I tried hobby and aquarium shops, but no one sold tubing with that small a diameter.

I managed to find a product at my local fishing tackle shop believe it or not called 'lumo tube' which is fluorescent tubing used as a lure for night fishing, and that did the trick nicely. Three meters for $6.00 also fitted my budget perfectly. You will only need approximately 60cm to do the job, so perhaps you can use the left over tubing and take in a bit of night fishing.

I have since discovered that medical drip hose would also be an alternative if you can get hold of some of that.

Step 7: Reassembling

Putting it all back together again, is just a simple reversal of the steps you took in pulling it apart.

Step 8: Helpful Tip

Once your flush button no longer works, rather than using a bucket of water each time to flush the toilet until your problem is fixed, remove the cover plate, and just lift and release the discharge valve.

Step 9: Video Tutorial

Over time, I have saved some serious coin by watching someone else's video on how to fix something and repairing it myself, so hopefully someone will benefit from mine.

Here is a 6 minute video I put together to further detail the process.

Fix It Speed Challenge

Participated in the
Fix It Speed Challenge