Pneumatic push button flush not working, how to fix it?

[chesl73]

Hi all

I've got an inbuilt pneaumatic push button cistern (came with the house) and the full flush is not working. The half flush works but isn't great. When I take off the cover plate I can unscrew the 'thing' from the cover plate and when I manually use my finger to push in the plunger there's no resistance and the plunger just gives and then returns back.
The tubes lead into the wall cavity with pretty much no access.
Any ideas on what might be wrong and how I can fix the full flush?

Thanks.

 

[SimonG]

Bellows may have gone on the push button. Have you tried swapping the little tubes over to test?

 

[Ben-gee]

Can also be the tube connections; it stretches or goes stiff over time and then leaks air.
Try cutting off 3/4” and reattaching the tube.

 

[rpm]

Can also be the tube connections; it stretches or goes stiff over time and then leaks air.
Try cutting off 3/4” and reattaching the tube.

Although I have given a like often just cutting back with a sharp pair of scissors by 10mm works.

 

[Ben-gee]

Although I have given a like often just cutting back with a sharp pair of scissors by 10mm works.

I misread the flag as America!! Hence three quarters of an inch!!!

We’re on the same page!

 

[chesl73]

Thanks for the replies.
I tried cutting off an inch of the tubing and reattached it but that didn't work.
I have the same toilet upstairs and I swapped the bellows around and the bellows are fine.
One thing I noticed when I took off the back plate (see picture) is that when I move around that white plastic piece that is holding the metal tube, when I now flush the 1/2 flush works and the toilet flushes. But I have to wiggle this plastic piece as it changes the angle in order for it to work and to refill properly.
I don't know how these things work and can't find any documentation to help me explain it so do you guys know how this plastic thing is supposed to sit in order for the 1/2 flush to work?
I noticed that (as per my attached) - this one piece rises when I flush which then in turn flushes and this other bit drops down. As I say though, depending on how I move the plastic bit this changes.
Any ideas would be appreciated.

 

[SimonG]

Looks like something has snapped. Compare with other toilet to compare.

 

[oz-plumber]

The plastic but is meant to sit flat / horizontal and clip into something on the front and back of the cistern.
With that piece not being correctly fitted, could be the cause of your problems.

FWIW, I gave up working on those cisterns a couple of years ago.
Parts way too expensive and labour times difficult to justify.

Too much grief from customers, so decided to make life easier.