Geberit - leaking

[nsm]

I hope you can offer some help.

I have a geberit concealed system for the toilet. Don't know exact model number, as I did not fit it.
Yesterday after flushing it just carried on dribbling water into the pan.

I opened from the 2 flush buttons at the front (not a very big opening) and after pulling and pressing a few things managed to see the part that was making the water continually flow into the pan.

All I have done so far is to raise that piece by way of an elastic band. As you will see in my attached picture.

That is all I have done so far.

I am now after some help on what to do to keep that piece raised, i.e. I am assuming under normal conditions this piece raises when the tank is full...

Bearing in mind there is very little space to manoeuvre can you help with what I need to do to fix my problem?

I am also not familiar with the names of the components, so please try to explain in a somewhat novice way if you can.

Other threads at this are a bit complicated to follow....

 

[oz-plumber]

You have to replace the flush valve rubber. Its at the bottom of the mechanism on the lower right of the picture.
These models cisterns have sometimes been a real problem and it may be worth replacing the flush valve itself.
Can be tricky - you may have to dismantle the valve inside the cistern to get it out. Then to put the new one in - you may have to dismantle and reassemble the valve inside the cistern to get it into place.
If its your first time be prepared for some real headaches.

 

[nsm]

Thank you Oz.

I will check it out tonight.

Dont like the idea of the headache though!

 

[nsm]

Hey Oz,

I couldn't get the flush valve out, however it appeared that it wasn't sitting properly so I pushed it into the hole at the bottom and the leak stopped. I read that these things are meant to clip in, but this one does not appear to have those clips. Instead I have just pushed the flush valve in as much as I could. Though I fear someone who presses to hard or continually will again unseat the whole piece and the leaking will start again.

Anything I can do to keep it in place you think?

I couldn't actually get the existing one out of the unit due to no space, so unless the new one comes in bits, there is no chance.

I see what you meant about the headache now!

 

[oz-plumber]

squirt some washing detergent in the cistern.
This helps lubricate the plastic.
It may be that the plastic has lost its shiny coating and is not sliding as it should.
Don't worry - we replace quite a few of the mechanisms. They generally only last 3 or 4 years.
Once they start causing you problems you just have to start replacing parts.